Who the Fuck are You?

Have you ever run into someone from your past unexpectedly and their reaction to seeing you makes you stop to consider the person you used to be? That happened to me yesterday but it wasn't the first time. In fact, this would mark the third time I've run into this person from my high school days who basically turned away when he saw me. Huh. The way I remember it, he was a total fucktard in high school who acted as if maturity was a bad word. We never actually got along but I didn't consider it any great loss. So what does it matter now? Well, for the most part whenever I run into people I used to see on a daily basis they're friendly or at least cordial. The way this guy reacts to me is so completely unexpected it just threw me for a loop. I initially laughed it off, but the more I think about it the more I wonder. Was I that big of a bitch to him that all these (nearly twenty) years later, he would rather act is if I don't exist at all than neutrally acknowledge my existence?
The first two times I saw him were both at our neighborhood grocery store. Yeah, this guy lives in my neighborhood somewhere. Funny. Both times he glanced at me, then so obviously looked away and kept walking it made me laugh. Then yesterday I ran into him at the elementary school. We were both there to present at career day but I didn't catch what he does for a living. I walked into the room, saw him and smiled (I think I even mouthed "hi") and he immediately turned his head away. I had to fight the urge to laugh out loud. It wasn't really a big deal to me then, but now it kind of bothers me. I don't really care that I'm being ignored. I care that I might have been so horrible to him years ago that he just can't get over it.
Well, the truth is I'll probably never know one way or the other. Our former mutual friends no longer talk to him and I'm sure as hell not going to try. Ah well, no sense losing sleep over it.