Originally Posted by
merlinextraligh
I've found smiling and waiving can be quite effective. It pisses them off that they didn't get the reaction they wanted.
And +1 on the camera phone if things get ugly.
This is my favorite way to handle it. It confuses the fire breathing knuckle draggers and generally forces them to sheepishly drive off as the veins visibly pulsate on their heads. Its especially effective if they have a mouth breather with them. Gives me great joy.