The rhetoric in this thread is getting out of control.
A bike is a thing. Buying a bike made me happy. I've ridden it 25,000 miles in the last 6 years.
I also run. Could I run instead of bike? Would that avoid buying that bike thing. Yes. Am I nonetheless happier because I bought a bike? Yes, because I enjoy biking more.
Buying things can bring you happiness, and while it is true that normally experiences are better, some of the things you buy are for those experiences. It's why even though running shoes may be a thing, running shoes can make you happy, because running in them versus work shoes or no shoes or any other kind of shoe is more pleasant (for most of us).
A lot of you are focused on the car as a thing. But I'm fairly certain the OP said that he wanted to drive it all over the place in some kind of way that made him happy. That's an experience. Is it true that he might get close to the same amount of joy with a lesser item? Maybe, but the OP's suggestion was that the car was for him an experience.
Go to a track event sometime and see how happy driving cars can make some people. Then consider that maybe the activities that make you happy might just be different than the activities that make other people happy.
And just to show how absurd this has become. Of course, he could bike rather than drive. But that would require buying a thing. Or maybe he could walk rather than bike. But that would require shoes, and thus a thing. So the question that OP referenced is not whether a thing in of itself has value, affected OP's colleague's material wealth, etc. It was whether OP's colleague's belief as to what would make him happy and working for that with no financial consequences to him was ridiculous. While it might not be what many of us would do, ridiculous is a strong term when you're talking about how much others will value a particular experience.
And don't get sanctimonious about costs. Most of us are saving hundreds of thousands of dollars for early retirement so we can fund ourselves, not so that each dollar can help another person in need. This is not a moral issue, although there was a very long thread on that (Sol's, I believe) and the nicer than necessary shoes, nicer than necessary house, nicer than necessary clothes, any "fun activity" things you buy, etc., all suffer under the same analysis of that could have been another dollar that someone else could live on.
I understand the potential environmental impact, but that's an area we could all do better at, and it wasn't the thrust of the question posited by OP.
Indeed, this thread is starting to convince me to buy a race bike because I have ridden the crap out of mine and worn it down, and I'm starting to get more clearly that sometimes you can buy things that do bring you happiness, and that's perfectly okay if you're able to afford it and have done the math on whether working X more days/months/years is worth it. Like buying a plane ticket to Europe. Or hiking boots. Or whatever else may float your boat.
But don't buy a boat, because those really are a waste of money! :)