If...

[Kami]

All theoretical ramifications of time travel aside, and grasping the true spirt of this thread before it gets bogged down in time paradox conversations, I might go back and give myself a little pep talk back in high school to not slack off at all and just generally give myself the knowledge of what I know now, so then if I knew more then than I know now, I would know then what I know now plus whatever else I pick up along the way. I know more now, then I thought that I knew now, or something like that. Screw everybody else. Other than that I don't think I'd try and erase some evil person from history. Maybe I'd punch a couple people for shits and giggles, other than that, meh.