You find yourself wanting something so much—a new computer, a partner, a house, more intellectual freedom, more friends, etc—and then once you have them, the goalposts immediately shift. Those things you wanted so badly become normal, no longer something worthy of special aspiration, and now you simply find yourself wanting the next thing.
Often, the next thing requires even more resources, time, status, etc—and so this phenomenon prevents you from ever happily “living within your means.” It also reduces optionality, since now reducing your means would make the next rarified object of desire impossible.
It’s certainly been pervasive in my experience, and it seems fairly universal.
Hedonic adaptation is certainly one element of what’s going on in here, but I also notice subtle feelings of Unsatisfactoriness driving the action. Yes, I hosted a great dinner party, but it’s a shame that my asparagus dish was flawed in a particular way, that this person didn’t seem particularly engaged in the discussion, that this other person never replied to my invitation, etc. Even wonderful things have elements of disappointment in them if you look closely enough. At least for me, this drives the treadmill too.
Buddhism suggests noticing Unsatisfactoriness and letting it pass, rather than identifying with it, or with feelings of grasping.
Stoicism suggests the Negative visualization exercise.