I had a young guy pull into a parking spot in front of me, and he missed me by millimetres. As i went around him I said "Watch out you Idiot", which was much more polite than I felt like being at that time. This guy, who looked like he was all of 5'1'' and weighed all of 55kg, starts swearing at me, no doubt trying to impress his beloved girlfriend in the passenger seat and the crowd waiting outside an adjacent fast food outlet. Given my "nearly hit by this dopey driver" mood, I slammed on my brakes, uncliked from my pedals, and started to storm back to the car. Now I am not a small person (6'1'' and at that time about 123 kg) and normally quite a passive person, but my mood must have been reflected in my demeanor. This guy starts shrinking down in his seat and starts saying "I am sorry Mister" (which made me think - I really am getting old!). I then politely but assertively pointed out that he was in the wrong (which he accepted), that he was an idiot (which he also accepted) and that I had pointed out he should watch out (which he agreed he should do in the future. He apologised for swearing at me. I got on my bike and rode off, feeling mighty pleased with myself.
Not 3 minutes later the young guy rides past - I saw him approaching and I thought "I'll give him a wave - I was a BIT TOO aggressive". He drives past, arm extended along with his middle finger. Anger restored, I then chased this little pr*ck. I could see him as I approached the traffic lights that he was stopped at, looking in his rear view mirror. Then the lights turned green, and the opportunity was lost. I was then really p*ssed - p*ssed that I was on my MTB, P*ssed that I was not fitter, p*ssed at this guy because he was such a jerk.
But then, what had I achieved other than a bit of unexpected max HR riding? Nothing. He is still a young jerk with limited driving skills with a cheap car trying to impress his girlfriend. If I was driving a car I am sure he would have had a similar attitude. While he was in his car he could be a smart@rse, but when the opportunity to flee is lost things start to get "real" for him. And I believe that is the reason why a minority of motorists throw items or abuse at cyclists - because they know they can probably get away from cyclists.
Made me think about something a friend had heard of about road rage. If you are the victim of road rage, grab you mobile phone and point it at the rager as if you are taking images of them - they pretty quickly move on, as te possibility that you are recording their conduct (and therefore securing evidence) is enough to make them think "not an easy target".