One lesson I have learned:

Embrace failure, embarrassment, confusion, pain. Don't go seeking them exactly, but don't avoid them. If you are at all ambitious and adventurous in anything -- entrepreneurship, grad school, dating, whatever, then you will fail spectacularly and often. It will hurt. Badly.

But don't flinch. Consider it a good thing, it means that life has not forgotten you. As my Buddhist friends like to say, experience what it's like to feel pain. Remember that it will make a good story to tell your grandchildren, and try again.