Ain't Over 'Til It's Over

We all have those memories. You know the ones, where you look back and say to yourself, "How could I have been so dumb!"
Yes, we can explain/excuse our failure with  the usual accuracy of hindsight, but it doesn't help. It taps into that time in our lives when we were so young that we had to deal with our own inadequacies, those feelings of not good enough.
The difficulty rises when we can't let go of other things in our lives, those other times when we lost, when we failed, when we revealed to the world that we couldn't do everything perfectly. We can react to that many ways: falling into depression because we failed, obstinately refusing to give up or admit we had not succeeded, blaming others for what happened in an effort to elide any responsibility.
And there are those who are only too willing to play along. These are the people who, either out of a misguided attempt to comfort, or else punishing us over and over and over, bring up our failures, our mistakes from however long ago, re traumatizing all concerned and as a side-effect, giving themselves control of the situation. Such people seem unable to forgive or forget for reasons that do as much harm as potential good.
There are, of course, people who seem unable to accept when something is over and done with, so they continue to fight battles that have long since been truly won or lost. The election is over. You can stop the harsh messages now. The marriage is finished, there is nothing left but the bitter attacks. Family or friends tend to be the worst at this, dredging up events from long ago.
The answer "Let it go" is the correct one, but the hardest to do. But why hold onto pain, ever retroactive pain? Why tear the scab  off the healing wound? Could it be the old concept of reviewing something  again and again with the hope that sometime it will come out differently?
We don't need to be right all the time, do we? And maybe we need to move from obsessing on our failures to learning from them.