In their classic Your Money or Your Life, Joe Dominguez and Vicki Robin argue that the relationship between spending and happiness is non-linear.

More spending brings more fulfillment — up to a point. But spending too much can actually have a negative impact on your quality of life. The authors suggest that personal fulfillment — that is, contentment — can be graphed on a curve that looks like this:

Beyond the peak, Stuff starts to take control of your life. Buying a sofa made you happy, so you buy recliners to match. Your DVD collection grows from 20 titles to 200, and you drink expensive hot chocolate made from Peruvian cocoa beans. Soon your house is so full of Stuff that you have to buy a bigger home — and rent a storage unit. But none of this makes you any happier. In fact, all of your things become a burden. Rather than adding to your fulfillment, buying new Stuff actually detracts from it.

The sweet spot on the Fulfillment Curve is in the Luxuries section, where money gives you the most happiness: You've provided for your survival needs, you have some creature comforts, and you even have a few luxuries. Life is grand. Your spending and your happiness are perfectly balanced. You have Enough.

According to Dominguez and Robin, your goal should be to achieve Financial Independence, the condition of having Enough for the rest of your life. "Financial Independence has nothing to do with rich," they write. "Financial Independence is the experience of having enough -- and then some." This is achieved when your savings has reached a level that will sustain you at the peak of the Fulfillment Curve indefinitely.

As many Get Rich Slowly readers have discovered over the years, the exercises and advice in Your Money or Your Life can transform your relationship with money, helping to break your dependency on Stuff. It's a great book for learning how to align your spending with your values. It provides a roadmap to Financial Independence.

Where Your Money or Your Life is less good, however, is providing advice for what to do after you've reached this goal. What happens when you achieve Financial Independence? What happens when you have enough — and then some? Many people reach this place only to find themselves wondering, "What next?" It's an important question, one that's often tough to answer.

A surprising thing happens to people in their forties. After working hard, buying a house, and starting a family, they suddenly realize that they'd better start being responsible with their money. They begin reading financial books and trying to learn how to set up a nest egg for themselves and their families. It's a natural part of growing older.

If you ask these people in their forties what their biggest life worry, the answer often is, quite simply, "money". They want to learn to manage their money better, and they'll tell you how important financial stability is to them.

Yet the evidence shows something very different.

In the table below, researchers followed employees at companies that offered financial-education seminars. Despite the obvious need to learn about their finances, only 17% of company employees attended. This is a common phenomenon.

As Laura Levine of the Jump$tart Coalition told me -- and I paraphrase -- "Bob doesn't want to attend his 401(k) seminar because he's afraid he'll see his neighbor there...and that would be equivalent to admitting he didn't know about money for all those years."

They also don't like to attend personal-finance events because they don't like to feel bad about themselves. But of those who did attend the employer event, something even more surprising happens.

Of the people who did not have a 401(k), 100% planned to enroll in their company's 401(k) offering after the seminar. Yet only 14% actually did.

Of those who already had a 401(k), 28% planned to increase their participation rate. 47% planned to change their fund selection (most likely because they learned they had picked the default money-market plan, which was earning them virtually nothing). But less than half of people actually made the change.

This is the kind of data that drives economists and engineers crazy, because it clearly shows that people are not rational. Yes, we should max out our 401(k) employer match, but billions of dollars are left on the table each year because we don't. Yes, we should start eating healthy and exercising more, but we don't.

Why not? Why wouldn't we do something that's objectively good for us?

Barriers are one of the implicit reasons you can't achieve your goals. These barriers can be psychological or profoundly physical, like something as simple as not having a pen when you need to fill out a form. But the underlying factor is that they are breathtakingly simple — and if I pointed them out to you about someone else, you would be sickened by how seemingly obvious they are to overcome.

It's easy to dismiss these barriers are trivial, and say, "Oh, that's so dumb!" when you realize that not having an envelope nearby could cost someone over $3,000. But it's true. And by the end of this article, you'll be able to identify at least three barriers in your own life — whether you want to or not.

April is Financial Literacy Month in the United States. This is a pure and noble thing. I think it's great that there's one month each year devoted to promoting smart money habits. That said, it has become increasingly apparent over the years that most financial literacy programs fail. They don't work. And this isn't just me speaking anecdotally.

In a 2014 paper from Management Science, three researchers conducted a "meta-analysis" of 201 prior studies regarding the efficacy of financial literacy. Their conclusion?

Interventions to improve financial literacy explain only 0.1% of the variance in financial behaviors studied, with weaker effects in low-income samples. Like other education, financial education decays over time; even large interventions with many hours of instruction have negligible effects on behavior 20 months or more from the time of intervention.

To put it in plain English, financial literacy education makes no discernible difference in behavior. People who take personal-finance classes manage their money no better (and no worse) than the general population.

We're pumping tons of money and time into a fruitless endeavor. All of this push to promote financial literacy accomplishes nothing. Zero. Nada.

Why is that?

It probably won't surprise you to learn that I have some strong opinions on this subject. Today, let's talk about why financial literacy fails (and what to do about it).

Note: This afternoon (April 24th) at 4 p.m. Pacific (7 p.m. Eastern), I'll be part of a Facebook Live interview about this very subject. If you're free at that time, you should join us! Update: Here's the entire interview.

It's always fun when disparate worlds of geekdom collide. Today, for instance, I learned that the term "keeping up with the Joneses" -- a popular phrase in the realm of personal finance -- actually originated in the funny pages.

That's right: "Keeping Up with the Joneses" started out as a newspaper comic strip. As a comics nerd, one who especially loves comic strips, this makes me happy. (Note: For some strips in this post, you can click on the image to open a larger version in a new window.)

"Oh good," Kim said when I rolled out of bed yesterday morning. "I’m glad you’re up." She gets up at 5:30 for work most days, but I tend to sleep in. Especially during allergy season.

"Huh?" I grunted. It was 6:10 and I was very groggy. My evening allergy meds kick my butt. Plus, I hadn't had my coffee yet.

"Something’s wrong with the bathroom sink," she said. "Look. It’s leaking. The floor is soaked." She wasn't kidding. The bathmat was drenched. When I looked under the vanity, I was greeted by a small lake.

"Ugh," I grunted. This wasn't how I wanted to start my day.

Kim kissed me goodbye and hurried off to work. I pulled on a pair of pants, poured some coffee, pulled out the vanity drawers, and got to work.

I was worried that I might have caused the leak when I replaced the sink's pop-up assembly last month, but no. The problem was obvious: The hot water line to the bidet (which I installed in October) had worked itself loose. (By the way, I love my bidet. Too much information, perhaps, but it's some of the best sixty bucks I've ever spent.)

Fortunately, the fix was simple. I reattached everything, then added a light layer of tape to prevent similar problems in the future.

Note: As a safety measure -- to make sure I wasn't missing anything -- I took photos of the issue and made a trip to the hardware store to ask their advice. They told me everything should be fine.

This might seem like a small thing to some folks but it’s a big deal in my world. You see, I’ve never really been a DIY type of guy. I used to get overwhelmed by home improvement. I felt unprepared, incompetent.

More and more, though, I’m learning that I can do it myself. It just takes patience and perseverance. And the more projects I complete, the more confidence I gain.

J.D.'s note: Last week's talk by Vicki Robin was hosted by the School of Financial Freedom, a Portland-based organization I'm friendly with. At that talk, I met Naomi Veak, one of the school's coaches. She and I have a lot in common (grew up poor in small towns, attended the same college, etc.). I asked if she'd share her story with Get Rich Slowly readers. She agreed.

Have you ever thought how different your life could have been if you’d taken someone’s advice? What if I told you it may not be too late?

I recently rediscovered a letter my mother wrote to me when I was 19, attending a small liberal arts college in another state.

Towards the end of the letter, she told me to save it, so I did -- even though reading it left me angry and frustrated, and not a single word sunk in. You see, she was giving me financial advice after another tear-filled plea for money.

“Don’t expect your thinking to change overnight,” she wrote. “Give yourself time to feel the inward peace of mind that will eventually come.”

This “inward peace of mind” took me 25 years to achieve! How did I finally get there? My name is Naomi Veak, and this is my story.

A Poor Girl at a Rich School

I was a poor girl at a rich kid school.

It was a school I couldn’t afford, and I was surrounded by lifestyles I was ashamed that I couldn’t pay for.

This was only the beginning of a long struggle with finances, where the same money scripts -- unconscious beliefs about money that drive our behavior -- played themselves out again and again. (For more about this idea, see J.D.'s article about how your money blueprint shapes your world.)

I wanted money. I just couldn’t hold onto it.

Shortly after college, I became homeless. One friend after another was put to the test when I crashed on their couch for too long.

A year later, my boyfriend and I were living out of his truck on the cold and rainy Oregon coast. I remember sitting in the cab, crying as I counted our last handful of change. He later wrote about stealing a sandwich to split with me in a short essay he titled “Desperation and a BLT”.

Overwhelmed by credit card debt, I made an appointment at a debt settlement company to help me get things under control...only to continue charging to the same account a couple of months later.

Then my student loan debt doubled when I returned to school for another degree.

Financial independence and early retirement continue to attract mainstream attention. This is a good thing. Check that, this is a great thing. Of course, with this attention there are more naysayers and critics than ever.

One of the main criticisms of the FIRE movement -- and of frugality, in general -- is that those who seek FIRE are depriving themselves. Or leading lives of deprivation. On the surface, these two arguments may sound like the same thing but they're not. There's a big difference between "deprive" and "deprivation".

Here are the definitions of these two words:

• Deprive (verb) — Prevent (a person or place) from having or using something.
• Deprivation (noun) — The lack or denial of something considered to be a necessity. The damaging lack of material benefits considered to be basic necessities in a society.

That's all very academic, isn't it? Let's take a deeper dive into the difference between deprivation and depriving yourself -- and explore why one is actually a good thing.

The Difference Between Deprivation and Depriving Yourself

Life is full of choices, from the important to the mundane. Whenever you make a choice, you are by definition depriving yourself of the thing you didn't choose. When you choose to purchase a townhouse, you deprive yourself of a single-family home. When you choose to buy vanilla ice cream, you've deprived yourself of chocolate. When you enter one door, you leave another unopened.

Depriving yourself of something isn't necessarily bad. It's something we all do every day in the little choices we make. (As J.D. has noted, opportunity cost is what we give up in order to have the thing we choose.) Deprivation, on the other hand, is a different matter.

Look at the definition of deprivation again: The lack or denial of something considered to be a necessity.

To live in deprivation is to be lacking a need, not a want. Chocolate ice cream is not a need. You can deprive yourself of it, but that doesn't mean you're living in deprivation. (Although I'm sure someone out there who loves it may disagree.)

Clothing, food, and shelter are needs. To go without them is to be in a state of deprivation. But besides those, there aren't that many needs in life. By "needs" I mean needs in the strictest sense — those things we need to survive and continue breathing as human beings.

You might include access to medical care and access to transportation as needs. After that, though, it gets grey very quickly. Even transportation is a bit questionable as a need. You can live in a dense city all your life and walk to get food, clothing, and everything you need. I'm sure many do.

If you've traveled a bit outside of the first world, you quickly see how microwaves, dishwashers, TVs, and computers are just wants. Sure, some of these things might fall closer to needs on a spectrum of wants, but they're still luxury items.

Here's the curious thing (and the whole point of this article): By depriving yourself of things you want, you can protect yourself from a life of deprivation, a life where you lack the things you need. A little self-sacrifice in the short term can lead to prosperity in the long term.

If you're panicked because you still haven't thought of the perfect gift for the people on your Nice List, you'll be relieved to know you don't need to spend as much time as you might think looking for something thoughtful. You also don't need to run up your credit card bill.

Why? Because neither of these things is likely to be appreciated by the gift getter.

In fact, a 2008 study from Stanford University researchers found that spending a lot of time and money to select a gift doesn't make a bit of difference to the recipient. According to Francis J. Flynn, an organizational psychologist at Stanford, the price of a gift is more important to the giver than the getter. (Plus, most recipients actually prefer cash or something from a gift registry, such as their Amazon wish list.)

Last week, I was a guest on the new Fire Below Zero podcast. The interview was fun. (It'll probably be several weeks before the episode airs, though.)

Toward the end of our conversation, the hosts asked a question that my mind keeps returning to: "What's something you spend money on that other people might question?"

At the time, I had two answers:

• On the business side of things, I spend lavishly on gear. I buy top-of-the-line Apple computers, then pimp them out with as much memory and storage as possible. I recently bought some expensive audio and video equipment to help with the GRS YouTube channel. I pay a lot for this gear, but I don't regret it.
• In my personal life, I have season tickets to the Portland Timbers, our local pro soccer team. These tickets cost $1050 each this year (and I have two of them), or about $62 per game. The price increases to $1150 each next year (or about $67 per game). This might seem exorbitant to some people -- especially when you consider costs for parking, food, etc. -- but I'm fine with it. I get a lot of pleasure from these games.

This morning, my mind drifted back to this question again. It occurred to me that it doesn't bother me that I spend on either of these things, and I doubt that it would bother other people either. These are deliberate expenses. They're purchases I make mindfully and that bring me both joy and satisfaction. This is how money should be spent.

If I were to answer the question today (now that I've had a week to think about it), I'd say that my biggest spending problem is buying things that I might want to have in the future — but for which I have no use in the moment.

Let me explain what I mean.

By now, you've probably heard of the famous Stanford marshmallow experiment. Most folks are familiar with this fifty-year-old study and its conclusions. In case this is the first you've learned of it, however, I'll give a quick review.

During the late 1960s, psychologist Walter Mischel tested the willpower of young children (roughly four years old). A researcher would bring the children -- one at a time -- into a room where they had access to a selection of treats, including marshmallows. The children were told that they could eat have one treat right away or, if they waited fifteen minutes, they could have two. Then the researcher left the room.

https://www.youtube.com/watch?v=QX_oy9614HQ

While this study gave researchers an immediate glimpse at how children handle delayed gratification, it also yielded some interesting long-term results. In 1990, Mischel (and colleagues) reconnected with some of the kids from the marshmallow test to see how life had turned out for them.

This second study revealed that the children with the best self-discipline at four years old grew up to be more popular, more successful in school, and better able to handle stress. The kids with patience and willpower were less likely to turn to drugs and they were more physically fit. In short, the ability to wait fifteen minutes to earn an extra marshmallow as a preschooler seemed to be an excellent predictor of how well a child would be able to delay short-term gratification later in life in order to pursue long-term goals.

That's it. That's the marshmallow test. Seems simple, right? Yet this simple experiment has become one of the most oft-cited studies in the world of pop psychology. You'll find it in books about entrepreneurship, habit formation, decision making, and -- yes -- personal finance.

There's just one problem.