How to be Insulting on Public Transportation: Pretend to be foreign when the conductor asks for your fare and try to give him the wrong denomination of money.
Yo momma is so fat she uses a pillow for a tampon.
How to be insulting when giving directions: Point with four fingers when they ask.
How to be insulting at the library: Find the coziest reading nook and start snoring.
How to be Insulting in the Street: Walk along as if you have stepped in something unpleasant, by pretending to scrape your feet along the pavement, or rubbing your soles on any available patches of grass. Then look daggers at anyone walking a dog.