❝He who knows he has enough is rich.❞ -fortune cookie
Joseph Heller, the author of the novel Catch-22, is at a party with his friend. The party is hosted by a billionaire at his mansion. When the billionaire appears and starts walking down a spiral staircase, Joseph's friend nudges him - laughing a little bit. He asks Joseph how he feels about the fact that this billionaire made more money yesterday than Catch-22 has made in its entire history.
Without batting an eye, Joseph says that he's fine with it. He even pities the billionaire. Joseph says he has something that the billionaire will never have.
His friend, puzzled by Joseph's answer, asks what he could possibly have that the billionaire doesn't.
Joseph simply replies, "I have the knowledge that I have enough."
As humans, we tend to vastly overestimate how happy we will be once we achieve our goals. In other words, we underestimate how good we are at adapting to our surroundings. This is true both on the upside and the downside. While we are sensitive to changes in our situation, we get used to the absolute levels. For example, lottery winners are thrilled after winning the lottery but eventually revert back to their baseline level of happiness. On the flip side, people who become disabled tend to be very depressed upon learning that they can't use their body the way they once did, but eventually, get used to it and also revert back to their baseline level of happiness. Psychologists call this hedonic adaptation.
In other words, as you strive to be a part of a new group or earn a better lifestyle, you'll feel like you'll be happy once you get there. However, once you're there, you'll start to define a new group to which you want to belong, only to find out that you define an even smaller group.