Don't think we've had this one yet, but...
People who make a mistake while driving, cut you up, and then turn psycho on you when you have the audacity to sound your horn.
Case in point: I was leaving the Holiday Inn car park in Coventry - you can only turn one way onto the dual carriageway, so this leaves you having to go right the way around the roundabout if you want to go in the opposite direction, which is exactly what I did.
Cue white Corsavanman, who just jumped out onto the roundabout with total disregard for the fact that I was already on there, already level with him and leaving via the same exit. Never mind, there were two lanes off the roundabout, so I took the right hand lane.
The next thing I know, he's half way into my lane, trying to overtake the slower car in front. I blasted the horn as a reflex action, largely because it was too late to brake, and alerting him to my presence was the only sensible action to stop things getting expensive and messy.
He swerved back in, but as soon as I was clear, he was on my tail. Lights flashing, gestures out of the window. As we got to the next rounabout, he issued what I assume was a whole lot of verbal abuse out of the window.
I usually have the composure to just blow kisses at people who behave like this. It makes the point and seems to wind them up even further. But (confession time, and I'm not proud here) I was so wound up myself, that I just deliberately cut in front of him pulling out onto the roundabout.
I know, I know, it wasn't the right thing to do, but I reckon it was the only language that this
was likely to understand.