But isn't a life based on seeking personal happiness by nature self-centered, even self-indulgent? Not necessarily. In fact, survey after survey has shown that it is unhappy people who tend to be most self-focused and are often socially withdrawn, brooding, and even antagonistic. Happy people, in contrast, are generally found to be more sociable, flexible, and creative and are able to tolerate life's daily frustrations more easily than unhappy people. And, most important, they are found to be more loving and forgiving than unhappy people.

— Dalai Lama

from The Art of Happiness