I haven't consciously dealt with any of this since high school (20 years ago, holy crap).
Worst I've dealt with is the occasional panhandler who gets too close - tell them they need to step back and they always do. I wonder if I'm doing something right or if there just aren't many thugs that are that touchy here?
Funny thing is, with me going to a preppy high school, I never saw this behaviour until I graduated.
You step outside the class room and that academic veneer rubs off in a light wind.