What is, What can be, What could have been, and What was....
Children are What is. New, open to the world around them. No rules, no inhibitions. They just are.
Teens and young adults are searching for possibilities. They are out to do everything, to be some one, to create.
They're after "What can be."
In middle age, people first start looking back, accessing where they are, what they've done and "What they could have done."
In old age, they are "What was."
Constantly frustrated by a new world they can't understand or keep up with, spending their days reminiscing about "What was."