Guys whistling or humming. Yes, we know you're uncomfortable, be quiet.
The stand back and pelvis thrust. This is when the guy stands like two feet back from the urinal and then leans back and thrusts his pelvis way forward.
The both hands on the hips. Like the guy is trying to tell the urinal who's boss. Actually this is usually done by business-douche type guys. Maybe they have their hands permanently affixed to their hips to indicate their importance. A much more rare variant is the both hands behind the head position, aka the "urinal is giving me a blowjob" position. Both very creepy. Keep a hand on your hose at all times folks.
The no-unbutton. This is when you leave your pants buttoned and feed your weiner through the trap door in your underwear. Are you Hasidic or a Never-Nude ? No? Then stop it.
The talker. This is such an obvious social deviance that I hardly need to even mention it. There is absolutely no talking of any kind in a public restroom until you are both at the sink washing your hands. If there's some emergency and you need to talk to someone who's at a urinal, stand directly behind them, do not walk around to the side of them. If you are inside a stall you must never initiate conversation except for toilet paper emergencies. I've had several bosses that would break this rule; again it seems to be common among boss types who lose touch with social norms due to their inflated self-worth. I would get a call on my office phone like "hey I've got a question about blah blah can you come talk to me?" I say "okay, where are you?" , "in the can" , oh no no no you cannot call me for a meeting when you're in the bathroom.