The U-curve of happiness: Why old age is a time of psychological bliss - Ashton Applewhite

The U-curve of happiness shows that we humans are most content at the beginnings and ends of our lives. The famous midlife crisis is the trough of our happiness because it's a time when we have responsibility for people older and younger than us, and we grow aware that we may not fulfill the dreams of our youth. Children and people in their 80s are uniquely able to live in the moment and be happy because they live at a neurological and psychological sweet spot, respectively.