Investing advice, lottery numbers, sports outcomes, some other junk to help me and my family and I live better. Even if we aren't too hard up right now.
But the only "mistake" I would correct, would be outting my Dad when I found out he was gay. And let him come out on his own. This happened about 14 years ago, back when gay people were still beaten because it was "unacceptable". It caused me and my family a LOT of grief until homosexuality became accepted. I was 9, and I didn't really understand what gay really meant, or that it was considered "bad". It's really the only mistake I would correct.
But then, would I have to live those 14 years over again. At least I should be able to do a bit better in school.