Regret is a teacher who only shows up after the test. Still take notes.

Regret arrives too late to help with the thing it is about, which is why it feels like punishment rather than instruction. The information inside it is still good. Somewhere in the ache is a specific fact about what you value, what you were afraid of, or what you will not do again. Most people sit in the feeling and never pull the fact out.

Pick one thing you regret and write the single sentence it is trying to teach you. Keep the sentence and let the rest go. If another person is involved, deciding what you would do differently matters more than replaying what you did.