If you could travel back in time, what would you tell your 10-year-old self?
"Put down that chainsaw, and listen to me!"
That would at least get my attention, as I never carried a chainsaw as a 10-year-old.
Unfortunately, beyond that, I don't think 10-year-old me would get much out of it. Too broken and clueless. I'd have to come back when I was 14 or so to even start making headway.