Aging. It's what's for breakfast, lunch and dinner for man, woman and beast.
No one who's alive isn't doing it. It's one of the great unifiers that makes us all, at our core, the same.
Perhaps because it's what we all have in common that we tend to talk about it so much—and once you've passed, say, 21 (because at one point the government decided that legal drinking is ev-ry-thiiiiing), rarely does the conversation touch upon how great it is to grow another year older. Even though, as George Clooney has pointed out, the alternative to growing older is...to not.
The notion of aging well differs depending on who you ask, but most of the time we're talking about how we look on the surface: Our skin, our hair, our bodies, etc. It's a great mark of pride to "look so much younger" or at least not like whatever your age is.
Whatever that means.