Why do we get so many threads that begin with a benign encounter (albeit possibly slightly alarming) between a group of people that invariably end with a hypothetical scenario followed by the question "can I shoot them?"
The post nearly never mentions what state the encounter occurred in, time of day, the other person's (or people's) perspective or cite any relevant law.
The laws in your state are probably meticulously clear on when deadly force, the threat of deadly force or homicide are justifiable. You should consult them.
Barring that, since it's nearly impossible to find a state's laws online
rolleyes
, you should consult an attorney. Or, if your desire to shoot someone is so strong that you're wondering when you're going to get your "golden ticket" to drill some guy, just do it. The prosecution will be happy to explain all of the applicable laws you've broken.
Just my two cents, it seems this kind of question is a recurring theme here and I, personally, find the underlying mental exercise a bit unnerving.
The real answer is: It depends entirely on the laws in your state and the totality of the actual circumstances, pondering hypotheticals is just mental exercise and in this case (and the others I mentioned) it's in poor taste.
IMHO, IANAL, YMMV ect.
ETA: Did he actually indicate that he was angry with you or was it an assumption. It could be you were driving the exact make, color and model car he wants to buy one day and he was getting an action shot of you for his computer desktop wallpaper. Not all encounters are "the balloon going up" in most places. Heck, I talk to and drive near thousands of people a day and it seldom occurs to me that the mechanations of their daily business are malevolent.