The past is valuable. Learn from your mistakes. Learn from the mistakes of others.
Then let it go.
Easier said than done? It depends on your perspective. When something bad happens to you, see it as an opportunity to learn something you didn't know.
When another person makes a mistake, don't just learn from it — see it as an opportunity to be kind, forgiving, and understanding.
The past is just training; it doesn't define you.
Think about what went wrong but only in terms of how you will make sure that next time you and the people around you know how to make sure it goes right.
- Jeff Haden (modified by Amr Badran)