"In the end, people don't view their life as merely the average of all its moments-which, after all, is mostly nothing much plus some sleep. For human beings, life is meaningful because it is a story. A story has a sense of a whole, and its arc is determined by the significant moments, the ones where something happens. Measurements of people's minute-by-minute levels of pleasure and pain miss this fundamental aspect of human existence. A seemingly happy life maybe empty. A seemingly difficult life may be devoted to a great cause. We have purposes larger than ourselves."