That said it comes down to courtesy and safety. Whether a car is driving slowly and impeding the flow of traffic or a bike is doing the same, it isn't safe. Yesterday when I was driving to work there was a guy on a bike that was blocking a lane of traffic. The road didn't have a bike lane and he couldn't ride far enough over to allow cars to pass. He could have ridden on the sidewalk. I thought the guy was an idiot, he was endangering himself and others by his actions.
To me it's just common sense. When riding a bike I don't want to tangle with a car because I will loose. I'll do everything reasonable to keep myself tangling with traffic even if my "rights" allow me to be an idiot.
I've only tangled with a car once, and while technically it wasn't my fault I realize I could have avoided it. I was at an intersection and when the light turned green I pedaled away. A car the pulled away slowly and I was right beside him. He made a right turn into me just after the intersection. I was in his blind spot and didn't see his turn signal. Fortunately he made a very slow turn so I just scraped my leg against the side of his car and didn't go down. A very loud F bomb got his attention.
Expect people to do stupid stuff and do everything you can to be safe.
