Flipped off while driving

While driving between appointments today I was honked at and flipped off by the guy driving behind me. I guess he felt I was taking too long (and following too many rules) at the 4-way intersection. We were headed south, and I was behind a scooter (which he couldn't see). There were 2 vehicles at the intersection heading East. 1 eastbound went, then the scooter in front of me, then the guy behind me (Mr. Impatient) starts honking, then it's the next eastbound driver's turn, and I look in the rear view mirror and Mr. Impatient is flailing around in his van, throw "the bird" and (probably) cursing up a blue streak. I let the eastbounder go, then headed into the intersection. Mr. Impatient turns West and continues his rant. At this point I'm curious as to why he was out of his head with anger at me...so I go around the block to find out.

I see his van parked at a meter (an expired meter no less) as he was making a delivery of some sort...so I plant myself and wait. 2 minutes later the guy comes out and I catch him before he gets in his van and ask why he had flipped me off for doing nothing more than following the rules. His response (people from the South, don't take this the wrong way) was nothing more than redneck spew, with a few garbled bits of English thrown in. I figured out that his issue was that he thought I was letting 2 cars through the intersection before taking my turn. I told him there was a scooter in front of me that he probably couldn't see, and that deflated his sails a bit.

I'm unsure whether I should have warned him about such actions in the future. There are many drivers out there that would take a HUGE offense at that and come back at him with a baseball bat, crowbar or even a gun. He seemed to me to be a spiteful, hateful little fraction of a man, that wanted everyone around him to be as miserable as he was for having to live is life based on his actions and free will.

I drove off wiser and more calm than I was...he just drove off.