I believe I could be happy at any reasonable level of wealth at which I could pay my bills. I don't really have to live like a pig. But having money brings me an incredible sense of security. Just not having to worry is what I like best. That's much more important to me than a first-class seat, opera tickets, or a great bottle of wine. Freedom from worry.
I was pretty poor in college and med school. I remember traveling across the country as a young person, scared that my old beater would break down in the middle of nowhere and knowing that I did not have the money to fix it. I remember worrying about how I would make my rent and pay my electric bill. I remember going to the grocery store at the end of the month using the change in my jar, which was all I had. At one point, I had no phone. And there were a couple of months when all I ate was granola and peanut butter (granola was cheap in those days, before it became a fad like it is now. No one was eating it that much at the time).
I would not want to go back to any of that. I still like peanut butter but I believe granola is indelibly linked in my mind with bad memories