So today me and some buddies were driving back from Carrabba's, carpooling in one of their cars. While driving he looks over and sees two guys driving next to him in some crappy van, the passenger makes eye contact with him and gets angry for no reason and starts swearing at all of us, then the driver speeds up and his passenger spits on my friends car.
My friend ignored it and we went on our way.
I probably would've done the same, but it would've pissed me off.

What would you guys do?