Unfortunately life does not have an undo button like many computer programs do. I am sure we would undo many decisions and things we produced, so many that we might end up sitting in a prehistoric cave. And then, what would we do then? Start all over again. In the cave we will notice that life unfortunately neither has a do button and it will take many hardships to organize a more pleasant life and this again might produce unvoluntarily or voluntarily side effects that we would prefer to undo.
So we might better reconcile with what we did and of course try to do better.