Ok, not just one question ... sorry. I have several questions.
Suppose you are standing in line at the grocery store. Or, standing in line to purchase a ticket for a movie, concert, or whatever. Or, standing in line in an amusement park for a ride. So, you are standing there, with your wife/girlfriend or friend. You are standing in line, and there are about 30 people also standing in line with you. Then, someone cuts in front of you.
They say nothing at all to you, and they are a random stranger, someone whom you have never seen before. So, you say something to the effect of "Hey, the line starts way back there" while pointing in the direction of where the line begins. The person, obviously becomes irritated with you telling them that, and they turn around and say something rude and/or flippant (possibly using the f bomb). You then realize the situation has escalated, so you tell your wife, or friend, to stay in line so you can go and complain to a manager.
When you return to where your wife, or friend, are holding the place in line, the person whom cut in front of you then turns around to face you. In a sing song whiny mocking voice, and with a crybaby face, they ask "Oh, did the poor wittle little baby go tell on me? waaah!" and then sneer.
Now, this would obviously aggravate anyone. I would even think, some of the nicest, and politest and most helpful people on the planet would say something back. I don't think it would be polite. So, you say something impolite (possibly dropping the f bomb) to the person who not only cut in front of you, but is going out of their way to aggravate you.
This response that you made to the person's aggravating comments then elicits another action from them. They get in your face, then start poking your chest with their index finger while saying "Whatcha gonna do about it, huh? huh? you friggin tattle tale nazi!!" then they throw something at you that strikes you in the face. It doesn't matter what they throw ... could be a banana peel, a bottle, a sweaty sock .. it hits you in the face, and you are not exactly sure what the object was, so it becomes an unknown object.
You then realize that the situation has escalated to the point that this person might be willing to assault you (and, in effect, an assault has already taken place since they threw something that struck you in the face), and you begin to suspect that the person is planning on escalating the situation even further.
Do you walk away?
I would. But then again, I am not a highly trained police officer that helped establish a tactical response unit for a major city. Maybe his instincts are far different from mine. I don't know.
But .. who initiated the conflict? Was it the guy who cut in front of you, or you, who said something to him?