A guy definately has to try and take the high road in these situations. On the other hand to have something thrown at you and pops after turning your back to walk away deserves whatever comes next. I'm not much of a fighter, never have been but years ago after having some words with some dude who easily could have crumpled me, I too realised it was not worth losing any teeth over but he decided to push me from behind after I turned to walk away. I turned around and he got ready for a shoving match but I promptly gave him a knee in the groin that he will never ever forget, he went down in fetal position and I ran like a little girl. I felt guilty for about 2 seconds, he prolly can't have kids. Some guys just can't resist opening that can.
Still, it sure sucks to have to deal with that crap while you're trying to unwind, even worse I'm sure it taught him nothing.