Jeez Crimson you sound like you need some encouragement. He's the ******bag, w/o doubt.
I gather you're high school age. When I was your age and, to be honest, for quite awhile after I'd let my temper go freely and have said some things I'm not terribly proud of.
One difference was that when I was in high school I was getting ready to play college football and could rage with the best of them so the intimidation matches usually went my way. Of course I'm lucky I didn't run across an armed nutbag.
So flipping the bird ain't the best idea but the ******bag that comes unglued in front of his kid is w/o doubt the ******bag in this example.
Also, pay no attention to the professional hand-wringers who want to blame your finger for someone else getting run over some other time. If the driver is that unbalanced the position of yor middle finger is irrelevant.
