Car ahead of you driving too slow? Pass them. Ride their ass until you do. No questions asked. Nobody gets angry.
No room to pass? Make room. Lane split. Do whatever you can. Surprisingly the car you're passing and the oncoming cars completely understand. This is just how it works over here. Pass around a blind corner? Sure why not.
Camp out in the left lane? Never. You make your pass then you immediately get back in the right lane, otherwise there will be a large Mercedes or Audi flashing its brights, rolling up on you at 150 mph.
Merging. Just do it. Someone will get out of your way. If not, see "Lane Splitting" below.
Lane splitting. Seems to be practiced regularly, mostly by motorcycles and scooters, but sometimes by cars. Kind of hard to do with large panniers on. Still not sure if it's legal, but it's fun, and efficient.
Don't Hesitate. It will just confuse people. Pick your move and commit to it. This applies when you're a driver, rider, and pedestrian.
If all else fails... Just do whatever maneuver you want with confidence. The other drivers can see it in you and it doesn't matter if you have the right of way, or if what you're doing is legal or normal, the other drivers will generally accept it if you do it with style. Besides, I'm sure they see much crazier stuff in traffic on a daily basis.
It didn't take long during this trip to pick up some of the riding techniques commonly used here. It may seem crazy if you think about it in an American city, but it works in Italy. In fact, if you didn't adapt to their styles, I think you'd get eaten alive on these roads. My only fear is that I will take some of these habits back home with me and get in a heap of trouble.
Stay tuned for helmet cam footage...