I'm am about as placid as you could be right bear with me you will not find someone more unmoved by anything this side of a world record bid for most hemp product imbibed in an hour competition
But put me in around cars where people get silly and I can become somewhat slightly 'less relaxed' if you drive do not brake check me I will hit you
Do not try and fit in a gap that isn't there I will hit you
Now bearing in mind it seems cyclists get this behaviour thrown at them I've never felt the red mist for a cyclist as they don't generally pose a threat I do worry I won't see one and try and drive in a way where I am likely to do 'less' damage should I not see someone at a busy choke point or awkward junction rambling away now
Anyway yes there are people who do lack boundaries when placed under duress. I live with one every day and it takes so much control not to stop the car/bike and stop someone else attempting to drive.
There have been instances where I was not able to calm myself enough to avoid a confrontation
Operative word is 'most'... just takes one nutter who is off the scale of 'normal' to escalate a trivial passing moment into something out of hand.
Admittedly this could happen regardless of what we do!