What is money for? It has one purpose - to be spent.
I think the better case to be made is where the line is between reasonable wants and unreasonable wants. Nothing about what you have said makes me think that your want of a new Audi (?) is unreasonable given your situation.
I have a lot of respect for your opinion, DH, so here it goes:
The car in question is the new Audi A7, which is about $67,000 with the options I "want". While I've currently got a $30,000 emergency fund I won't touch, the only other cash I currently have saved up outside of retirement that I could put toward the car are the $4,000 in car savings account I've built up so far and the proceeds from selling my Acura, which I would sell for $4,000-6,000. Financing is available at Audi for 1.9%.
To me, it seems per se unreasonable to buy a car, particularly a luxury car "toy" when I don't have the money to at least theoretically buy it outright. On the other hand, part of the reason I don't have more money than that is that we save aggressively toward retirement, put an extra $500/month toward our mortgage, put aside $400/month to college funds, and give nearly $2,000/month to charity. If I wait until March, I could possibly get a large enough bonus to pay off most of the car, but that is never 100% guaranteed.
Is it crazy not to wait given these facts? The A7's are a little scarce (only 5,000 in the U.S. this year) and the color combo I want is hard to find and just happens to be at my local dealer.