Maybe there's a reason people say it all the time.

...it doesn't change the past.

But it can change your present. And your future.

[Hmm...that didn't come out as nice as he thought it'd would. He tries again:]

What I'm trying to say is...you made mistakes. Don't make'em again. It's not easy, but what's important is the trying. And the more you try, the better you get.

You weren't smart. But you can get smart, if you want to.