Comment by Arainach

Part of it is that it's a necessary mindset. When cycling, you have to assume that every driver is trying to kill you and every parked car is waiting to throw a door open and knock you off (and possibly kill you). Even where malicious intent is lacking, distracted driving is such a pervasive problem that you have to adopt a mindset of "everyone else is awful"....because statistically speaking, enough of them really are.