Funny cuz I've wondered if I had a time machine how far back I might go. LOL. But if we changed all of the bad to good, I'm sure there would be something else that showed up. We all are here to learn lessons that we need to learn and that is the bottom line. IF we learn them, well then we are better for it. If we don't, we just keep repeating.
If you focus on the past, you ruin the future. You can only live for today.