" In particular, Vaillant says, it is the experience of loving and being loved that most closely predicts how we react to the hardships of life; human attachments are the ultimate source of resilience. “The seventy-five years and twenty million dollars expended on the Grant Study points, at least to me, to a straightforward five-word conclusion," Vaillant writes. “‘Happiness equals love. Full stop. "

― Jonah Lehrer , A Book About Love