What if everyone you know are awful jerks? Be nice to hit the reset button for them. And any _real_ friends will just become reacquainted with you again.

I'm guessing it'd be some kind of amnesia, and you'd realize you have amnesia.

If I forget my friends they'll take the time to remind me of who they are. But if they all forget me they'll be like "Who is this weird freak who says he knows us?"