Indeed; I once almost caused a pile-up in Florentine rush hour by trying to stop for a red light. It was amazing: chaos at 40-50 kph dense urban traffic, scooters everywhere, 3 lanes squeezed out to 6; and I'm the one who almost caused the accident in my rental Skoda trying to follow traffic laws (but not 'rules', obviously). I leartned very quickly that I needed to go with the flow.
Incidently, that's also how motorcycles stay safe; not by following the rules exactly, but be reading the action, interpreting, and reacting intelligently, even if not legally.
I live in CA, so lane splitting (or lane 'sharing' as my peace and love traffic engineer buddy with an oilhead Boxer calls it) is legal, but I get the sour face thing, too. Jealosy? I'm sure that's in the mix along with frustration, ignorance, and plain old pissy attitude. I use judgement always; I don;t always take the split, and almost never over about 35 mph. I find it a bit spooky when somebody splits at 60-70-whatever; why bother? And for the record, I've seen the 'hooligan' thing just as much on hogs as rice rockets; the main difference is the speed....
I say ride smart, be courteous in a rational manner, and seek the flow of traffic, not the letter of the law or what you think ought to happen. No matter who is 'right', we will always lose a face off with a car.