Donald Hall said this quote

[O]ver the years I travelled to another universe. However alert we are, however much we think we know what will happen, antiquity remains an unknown, unanticipated galaxy. It is alien, and old people are a separate form of life. They have green skin, with two heads that sprout antennae. They can be pleasant, they can be annoying--in the supermarket, these old ladies won't get out of my way--but most important they are permanently other. When we turn eighty, we understand that we are extraterrestrial. If we forget for a moment that we are old, we are reminded when we try to stand up, or when we encounter someone young, who appears to observe green skin, extra heads, and protuberances.