You can't UNfeel a feeling.
You can't UNdo a deed.
You can't UNsay a word.
You can't UNgrow a seed.
You can't UNtaste a flavor.
You can't UNsee a scene.
You can't UNhear a sound,
Or UN-eat gassy beans.
You can't UNbreak an egg
That splattered on the floor,
Or call back opportunities
That wandered out the door.
You can't turn back the clock,
And that can make things tough,
But you CAN do better next time,
And THAT is good enough.
No, you can't UNdo the past
Or UNspill any spills,
So let go of the UNs, my friend
And focus on "I wills".
-B.C. Byron

This simple poem is one of my personal favorites. I read it when I need a boost after I’ve made a blockhead mistake, which happens frequently.
Like all emotions, guilt and regret have an important purpose. Our desire to undo the past is NOT part of that purpose. Imagine if you were given the ability to time travel and retry any time you want. You could go back and wipe that embarrassing bogie from your nose before going to the dance. Maybe you would take back a few words that shouldn’t have been said, or add a few words that would really zing that jerk who made fun of you at school. Personally, I would go back and tell myself to wear my wrestling head gear so I wouldn’t have weird cauliflower shaped lumps in my right ear. But how far would we really get with that power? I think it’s a near certainty that we would all end up in a constant redo loop, trying to get those moments perfect. We would end up with even more regret as we iterated over and over for eternity. UNs aren’t worth your time.
Regret can overwhelm and immobilize us if we don’t understand it’s real purpose. Guilt should be a motivator. Dwelling on the past is only useful if it helps us make plans for the future. I’ve known so many people who get caught up in a perpetual cycle of feeling unworthy and sad because of a few mistakes, and they seem to feel like being depressed is the best way to make up for those mistakes. Feeling down about a bad move is natural, but feeling cruddy doesn’t fix it. There simply is no undo button on our bodies or brains (unless that’s what bellybuttons do. Hmmm….). There IS always a next time, though. You are worth extra chances, lots of them. Just be a little better at something as often as you can, say sorry for real, and ask for help when you need it. That’s enough. That is enough. No depression or crippling regret necessary, friends.