If he was actively trying to block you from lane-switching, then he was the jerk, not you. Maybe there were other circumstances - dunno, wasn't there. Still, I hate being called anything by other drivers.
I don't know if I can quote my "worst" driving experience, but I'll offer up three of my most recent (and try to be quick about it):
1) A couple months ago, a blizzard rolled through while I was out on a work route. Our work vans are top- and back-heavy, which makes them unhappy on icy roads. We were, nevertheless, sent on an assignment a good 50 miles away, and along the way, I lost control and we slid off the road and into a ditch. It took 2 hours for a tow truck to come get us out. We were given an assignment after that, much to our irritation. On the other hand, it was sort of fun to watch the chaos all around us while we sat and waited - and we got to snooze for a while.
2) In the same van, I was in the middle of a tight right turn through an intersection. The light was changing at the time, so I was trying to be quick but safe - I didn't want to roll the van by whipping it - and there was a lady in the opposing left-turn lane who wanted the same road, with her SUV stuck in the intersection while I was making my move. I glanced in my rear-view and saw her throwing a massive tantrum because I apparently wasn't moving fast enough for her. Saw her mouthing some pretty unpleasant words.
3) Once more in the same van, we were fueling up at the end of the day, and an employee at that gas station was a friend of ours. We were schmoozing with him for all of 30 seconds after we were done fueling when a nosy old codger in front of us approached my window and snarled/cursed at me for holding up other cars. He didn't seem to notice there were 2 empty stalls and there was no immediate traffic.