Is there anything you've done in your life that you think of certain things you do now as penance or self-punishment for?

I did something once that I am so ashamed of that I’m not going to mention it here (which I suppose doesn’t do much to invite openness, but oh well), for which I am still “doing penance”. This isn’t a religious thing, it’s just for me. There are certain unpleasant tasks that I intentionally take on even though I don’t really have to, and I think of them as something I have to do because of what I did in the past. Does anyone else do this/think this way?