If you look back only at your mistakes, you'd think you were an idiot.
If you look back only at your wiser choices, you'd think you were infallible.
But if you look back at everything, you realize you're a human being who has been through a lot, grown a lot, and is always still learning and improving as time goes by.
It seems like people who have a very low opinion of themselves remember too well a lot of their mistakes, and people who are egotistical forget they've ever made any.
Remembering you've made some allows you to be more forgiving of others.
Letting go of punishing yourself for things that can't be changed allows you to move forward with a greater sense of confidence and self worth.