I have a few sticky notes on my wall at work.
One of them says, "Never Stop Learning".
In life it's important to always remember that:
1. You're not the only one that knows stuff. Lots of people older and younger than you know a lot, and you can learn a lot from them
2. When you mess up, you should take it as a learning experience. Don't do the same thing again.
3. When we stop learning, our brains start slowing down, thus producing memory loss, increased stupidity, and many other random problems. (I have all these even though I keep learning, so there may be other causes as well.)
4. I don't have a 4th point. You just wasted 5 seconds by reading what you thought was going to be a 4th point :P