When I'm wrong, I feel pretty sheepish and will wave and call out "Sorry," right away if the situation permits.

As to the various and sundry honks, close passes and the like (even a cigarette butt one day), I haven't been very creative lately. If I think the impatient jerk has half a chance at hearing me, I'll just call out my default, "F**k off!" Frankly, in traffic I'm scanning the whole panoply of immature boneheads--one of them actually trying to engage me one-on-one is an unwelcome distraction (and earns my std response).

And yes, if someone actually wants to stop and discuss it, well, "I'm your huckleberry..."