Answer for question 4602.

[Error: unknown template qotd]I would never do it. Even a very small change in past events can have huge consequences. If I went back at any time earlier than 1990, I might never have ended up marrying Kathy (and in fact any change up until the wedding could do that). Sure, there's things I regret doing and would like to change, but the likelihood is that I'd cause something -- maybe a LOT of somethings -- to change in a way I didn't like.