think were all probably guilty of this at some stage of our lives....
anyway f**k it, put your brakes on, slow right down ( this is hypothetical as its techincally roadrage and probably illegal), encourage him with a few wayne kerr signs and then signal him to come off..
then smack him round the head with your wheel brace.
job done, and he wont do it again..(or anything else for that matter as you'll probably have killed him)
failing that, let it wash over you...he's probably a kerhunt with nowhere to go and is trying to get there quickly...sit back, relax and be comfortable knowing what you know...
now sleeep...