My friend happened to cross another driver a few years ago without knowing it.You can always non-aggressively get out and go look at the back of your car. Then just tell the idiot you thought he was signalling you that something was wrong with your car.... hanging bumper, flat tire....
The other guy honked, yelled, screamed and then finally came out of the car to talk to my buddy. Buddy takes his seatbelt off ready for a fight so he's not tangled up and can jump out easier.
Other drive came to apologize for his behaviour and wanted to talk to my friend face to face.
Could have very easily gone another way.