Don't Dwell On Past Errors In Judgment

Do you worry too much about what you did days, weeks, months or years ago in your writing world? I think a lot of us spend more time than is good for us regretting the way we wrote a story or a response to an editor when a story was rejected.--even a scathing critique we might have given someone who wrote a god-awful story. How many times can we tell ourselves--I wish I had...  or I never