When you are young, your potential is infinite. You might do anything, really. You might be Einstein. You might be DiMaggio. Then you get to an age where what you might be gives way to what you have been. You weren't Einstein. You weren't anything.
That's a bad moment.
I wanted to be a writer once. I wanted to write something that someday some lesser person would quote, but I never did. I'm the lesser person.