The couple of times this has happened to me, I've found that staying calm when someone else is ranting at you makes them even madder. Same thing happens when you start taking pictures with your cell phone. In retrospect, the best thing to do might be to make a show of talking on your phone while they are jumping up and down beside your stopped car. If they think the police are on the way, they might show a little self-restraint - and then run.