If you haven't seen it, Dan Gilbert's TED talk -- "Why are we happy?" -- presents some good experimental results on this topic. http://www.ted.com/talks/lang/en

If you haven't seen it, Dan Gilbert's TED talk -- "Why are we happy?" -- presents some good experimental results on this topic. http://www.ted.com/talks/lang/eng/dan_gilbert_asks_why_are_we_happy.html http://www.ted.com/talks/lang/eng/dan_gilbert_asks_why_are_w... The Wikipedia article (and even the choice of the word "treadmill") suggests that people maintain a roughly constant state of happiness despite improvements in their life. But it also works the other way -- people return to a baseline of happiness even with huge disasters in their life.