Most people tend to move toward a happiness "set point" after good things or bad things happen to them. Philip Brickman and Donald T. Campbell coined the term "hedonic treadmill" to describe this phenomenon in a 1971 essay titled "Hedonic Relativism and Planning the Good Society."
Wikipedia has a good article about the Hedonic Treadmill, citing studies that show lottery winners end up being about as happy as they were before they won.
[R] esearchers interviewed 22 lottery winners and 29 paraplegics to determine their change in happiness levels due to their given event (winning lottery or becoming paralyzed). The event in the case of lottery winners had taken place between one month and one and a half years before the study, and in the case of paraplegics between a month and a year. The group of lottery winners reported being similarly happy before and after the event, and expected to have a similar level of happiness in a couple of years. These findings show that having a large monetary gain had no effect on their baseline level of happiness, for both present and expected happiness in the future. They found that the paraplegics reported having a higher level of happiness in the past than the rest (due to a nostalgia effect), a lower level of happiness at the time of the study than the rest (although still above the middle point of the scale, that is, they reported being more happy than unhappy) and, surprisingly, they also expected to have similar levels of happiness than the rest in a couple of years. One must note that the paraplegics did have an initial decrease in life happiness, but the key to their findings is that they expected to eventually return to their baseline in time.
In a recent issue of the Experimental History newsletter, Adam Mastroianni presents five tools to help people enjoy good things that they've stopped enjoying because they have adapted to them. The tools are:
- Disruptors, which "refresh pleasant experiences by interrupting them"
- Cutoffs, which "can prevent the inevitable dip in pleasure that comes at the end of most things"
- Variators, which are "little modulations that keep experiences fresh"
- Recyclers, which are ways reminding yourself of good past experiences
- Peaks and finales, which are ways "to make the best parts better, the worst parts less bad, and the endings universally good"
Here's more about the first tool, Disruptors:
Most nice things get less nice over time, whether it's a slice of cheesecake, a massage, or houseguests. Disrupters refresh pleasant experiences by interrupting them.
-Commercial breaks — people actually enjoy TV more with commercials
-Short matches in online gaming. Notice that most shooters make team deathmatch last ten minutes or less!
-That afternoon when someone is staying with you and they go see another friend who lives in the same city and you go to work or stay home and do laundry or whatever