Every single one of us will at some stage have a thought like: "If only I had not done this..." or "What if I had done this differently?" I have asked myself questions like that quite a lot during the last few months, esp. during the last few days - which is silly because I know perfectly well that there is no way to ever turn back time. And if we could, wouldn't we at the same time also erase all of the knowledge we have collected?
Time travel, however, would of course be a different story: what if you could travel back to one point in your life with all the knowledge you have now? To which time in your life would you go?
Would you have a bad conscience about the things you changed?
I guess, it's not much point thinking about this - and we certainly should not live in the past, however, looking at your past and learning from it, is a good thing. You need to understand your own history and see where you have gone wrong. It's always hard to admit that you've done something wrong or simply that another path would have been a lot better for you.
We can't change the past but we can work on creating a better future by focusing on the things we can do right in the present. If there is something you want to do, something that would make a positive difference in your life or in someone else's life: what keeps you from doing it?