Buy moments, not stuff. According to Dan Gilbert, Harvard University psychology professor and author of Stumbling on Happiness, the key is to spend your money on experiences rather than material things. Material things, even if they’re expensive or you wanted them badly, tend to lose their luster after a while, literally and figuratively. Memories of people, places and activities, however, never get old. In a survey, Gilbert found that 57% of respondents reported greater happiness from an experiential purchase. Only 34% said the same about a material purchase.