Now, I've reconciled myself to the notion that the guy is a bit of a jerk. I used to call him my nemesis, but I've softened on the archenemy position because he was humanized by a fellow classmate. So he's been downgraded to amusing to look at (he's kind of nontraditionally attractive and pretends he's not emo even though he wears purple skinny jeans and vests while carrying his skateboard unironically, of course), not stupid just quick to judge and a little narrow minded and elitist, but entertaining in that 'oh, of course you're going to take the contradictory position to me' kind of way.
But drifting off? Really? During a 20 minute presentation?
And when I called him on it during the break, he shrugged and said that I shouldn't take it personally - he apparently drops off in another class we share (this one with 4 more people in it) all the time.
The only reason why I didn't throw my shoe at him was because I was too lazy to take it off. And the knowledge that he wouldn't actually understand why I was throwing it in the first place. On the up side, I think the presentation went well for the other two people.