Daniel Gilbert, a Harvard psychologist, surveyed two wildly different groups – recent lottery winners and recent amputees. Initially, the winners felt a dramatic rise in happiness; the amputees, a notable loss of happiness. Within three years, though, most winners and amputees had adjusted to their circumstances and were roughly as happy as they had been before their “life-changing” event.

There’s also a theory that people blessed with a great increase of wealth, fame or status are plopped onto the “hedonic treadmill.” “You become rich, you move to Rancho Santa Fe,” Christenfeld said. “Now you are the same wealth as all of your neighbors.”

Instead of a source of how’d-I-get-so-lucky? happiness, your new wealth quickly becomes the normal condition of your life.

Howstuffworks