Certainly in Britain there is a perceived idea that 'road rage' is on the increase.
I've only been commuting since last October so my experiences are relatively limited -
I meet a surprisingly high number of 'bullies' for example, I daily have to cross a narrow bridge (just wider than a single car) where there is clearly signposted priority to one direction, and it's far from uncommon when on a bike to be forced to give way to a car that should wait for me. Similarly I've had several incidents of cars pulling out of side roads, deliberately forcing me to brake to avoid hitting them, and few of these have been due to inattentiveness.
Yes I also get drivers who pull out and give me plenty of room, but probably no more than squeeze past to avoid slowing down.
Probably most drivers are pretty neutral in their behaviour, but cyclists do seem to provoke a minority of drivers into inexcusable behaviour.
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Currently riding an MTB with a split personality - commuting, touring, riding for the sake of riding, on or off road :)