All the childhood friends that I have some degree of contact with seem to have turned out OK. The worst one really is the guy who turned out to be a libertarian, conspiracy-theory believing (chemtrails, OMG!) Trump supporter.
From time to time I do wonder about the pair of brothers who were in my mixed 4th/5th-grade class who were pathological liars. While 10-year-old me thought they were just lucky kids who had incredibly awesome experiences in their lives, I later had the epiphany that they were most likely pathological liars. (This after other run-ins with that type over the years. For a while I suspected they were drawn to me somehow.) Anyhow, better to leave some stones unturned, right?