Psychology says the emotional turbulence of youth doesn't last — older adults report fewer bad days, recover from the bad ones faster, and hold steadier moods than people half their age, as if the heart, unlike the knees, actually improves with wear

There is a man in my building who is somewhere north of eighty. Every morning he rides the lift down with a small dog under one arm and a folded newspaper under the other, and every morning somethi...