For the most part I don't really disagree with you, but there are ways drivers could behave unpredictably out of what might be called an excess of caution. For

For the most part I don't really disagree with you, but there are ways drivers could behave unpredictably out of what might be called an excess of caution. For example, my wife just yesterday told me about something that happened to her that day. She was waiting to turn right from a side street, behind another car also turning right. The first car started their turn, she pulled up, checked that there was ample room, and so started to turn in behind them. Then the car in front slammed on their brakes, stopping partway into the lane. It seems they did this because there was a car approaching in the distance on the main street. The thing is, that car was far enough away that both cars could have easily turned in front with room to spare. My wife had seen it before starting her turn, and realized there was plenty of time. In fact, after a few seconds, the driver in front of my wife realized just how much time they had, and finally made the turn, still before this other car arrived. Because my wife is an attentive driver this wasn't a problem, but you could certainly see a driver in her position starting to make the turn while looking to the left, and rear-ending the car that suddenly stops for no apparent reason. Of course they would be at fault for doing so, but the first driver's excess of caution, if you want to call it that, would also be a contributing factor.