1. Buying a house 2. Deciding not to have kids 3. Deciding not to plan to live past 50-55
1. At my old apartment my neighbours had become obnoxious. The house is much bigger so I have more room to tinker, and my wife is much happier living here. If she's happier, I'm happier.
2. We've passed the age where having biological children is really feasible, and we really enjoy our lifestyle, so "formally" rejecting the pressure to raise children has reduced my stress.
3. I'm fine with living past 55, but I have historically been incredibly risk averse, especially with my finances. Deciding that I don't care if I'm poor or dead at 55 is a mental trick to compensate for my own neuroses. I can do riskier investments, risk my phobias, say what I think and buy whatever.
I'm aware these are pretty idiosyncratic.