Some places there's a usable shoulder, other places there's not. When I need to be in the lane, I am. (not on the Interstate). The cars around me are consistently courteous and cooperative, and I try to behave that way too.
I was thinking as I rode to work about Cherokee Schill and how much it would be a burden to have an adversarial experience to get to work each day and to keep a job. (Insert observation about penalizing workers who are working for their living and paying taxes; is bike tolerance a part of moving people out of the social safety net?)
Later I came across this story http://commuteorlando.com/wordpress/2010/10/01/the-cost-of-being-different/ about a Florida cyclist who was continually harassed by police for riding in the lane.
It's vehicular bullying: if it were a bulldozer, or an Amish buggy, or a mounted police officer they'd slow down, take their turn, and behave like humans. But when it's a single vulnerable cyclist and they've got more power because they're in a car and can intimidate with impunity, then they act up. Classic coward bullying behavior, driven by their own insecurity.
I think it's really important to be cognizant of the struggles that are being fought elsewhere, by people doing the same thing as I am.