Have you ever written code that was below your average quality? I have, and sometimes I wish I could have write it better then.
There had been times when I came across some of my older work, and I’ll be tempted to rewrite or refactor or rework the code or logic. Then I told myself that I did the best I could then, and I should let it go. Focusing my energy on future projects is a better use.
That said, sometimes your creations can come back and haunt you. Like in this animator versus animation video.