I didn’t know it then, but in making such a list, I was engaging in a scientifically based gratitude intervention, the sort that has been shown, in experimental studies, to make you an all-around happier and more sociable person. Since the year 2000, psychological research has tied gratitude to a host of benefits: the tendency to feel more hopeful and optimistic about one’s own future, better coping mechanisms for dealing with adversity and stress, less instances of depression and addiction, exercising more, and even sleeping better. The degree to which we’re grateful “can explain more variance in life satisfaction than such traits as love, forgiveness, social intelligence, and humor,” sings one recent paper. “Gratitude is strongly related to all aspects of well-being,” declares another.