This post is adapted from YNAB's twice-monthly newsletter, Loose Change .

Buying stuff is easy, understanding why we do it is not. Certain purchases can seem non sequitur: the loner who never invites anyone to his house but builds a bar for entertaining. The person who struggles to make ends meet but can’t imagine living without their high-end new car.

Some personal-finance experts make a living ripping people to shreds for decisions like this (more on that here ). They act as if spending money is simply an exercise in rationality. It’s not.

We spend to express who we are and who we want to be. And sometimes, if people don’t believe they can get where they want to be by staying on course (planning, saving, etc.), they try to leapfrog the process and spend money in a way that seems crazy or irresponsible from the outside.

I once worked at a fancy Cuban restaurant with a busboy named Jason who came back from his shift break and announced that he had just bought a $3,000 art print.…