Our "potential" is determined by our genetics and environment. I believe each human does his "best" and by that I mean, does what he thinks he needs to do to get the things he wants, based on his own priorities. For some people, this is sitting at home and playing games all day. For some it's writing an operating system. For some it's going to the moon.
Essentially I believe that any of us, at any given point in our lives: could not have done any better than we did. I believe we will always do what we want to do, and that's that. That will, that desire to do something by the way, it's just an illusion. It's an abstraction built upon the deterministic movement of physical phenomena.
I was told by about a million teachers in high school "oh you have such great potential, if only you applied yourself"
It took me until my mid twenties to realize that I was applying myself. I have a limited capacity for application.
Even if you aren't ultimately limited by your cleverness, your limitations in capacity for execution can thwart your career.
Thus I'm 25, no degree, hack for fun, contract work here and there, and otherwise I could care less. I can execute uninteresting work, but I have a limited tolerance for it. Perhaps its more of a blessing than I think though, because it's really cemented in my mind that I must make and sell my own products.
I want a degree. Maybe I'll get one someday.