Terrific post, Randya.
I maintain that the signs say "Share The Road". Sharing, I was taught as a kid, goes both ways.
As a cyclist, I ALWAYS ride as a single cyclist as opposed to riding in a group. Personally I have been caught in a long line of traffic following a group of cyclists riding in such a way, and in a no-passing zone, that prevents motorized traffic from safely passing. When I started riding I vowed never to do that. In two years, riding courteously and alone, I have never been intentionally buzzed, been yelled at or cursed at, or had anything thrown at me. Of course, it may happen tomorrow.
I also got caught in a Critical Mass once when I was driving home from work - a group of cyclists were approaching as I was exiting the parking lot and I courteously waited to pull out - I could have jumped the gun and probably gotten in front of them - but I was rewarded by them riding to the top of a single lane railroad overpass and stopping so as to block the entire road. This really ticked me off, and I was hoping for a cop to come along. Inexcusable behavior on the part of the cyclists.
I think most of these problems all go back to a lack of common courtesy. Just as drivers should yield to cyclists when the cyclist has the right of way, cyclists should conduct their rides in such a way as to not unnecessarily impede the flow of traffic - clearly an 18 mph bicycle is going to cause a safe driver to slow down if he cannot immediately pass, but at least by the cyclist moving to the edge of the pavement where possible facilitates the pass, and is likely appreciated by the motorist.
I've also been in situations where I was riding and a long line of oncoming vehicles was preventing a following vehicle from passing. I pulled off at an intersection and let the driver by.
Of course, sooner or later we may all run into the guy that just got yelled at by his boss, had a fight with his wife, or subscribes to the theory of "better living through chemistry".
As Rodney King said - "Can't we all just get along?"