You can only learn from a mistake after you admit you've made it.
Don't start blaming other people (or the universe) for the things that go wrong, because you distance yourself from any possible lesson.
We see mistakes and failure as shameful things. And we usually identify with them:
If I fail a test, then I am a failure. If I make a mistake then I am a mistake.
It requires three things:
When you can laugh at your own mistakes you know you've accepted it and no longer judge yourself on the basis of one single event.
Humor loosens up your psychology and prevents you from obsessing about the past.