I watched a programme a few years ago that traveled with 'white van man'(WVM) to see why he got wound up.
Through the day, WVM pointed out several pieces of bad driving and barked and bibbed at most of them. The presenter asked him how often days were like this, and was told "every day", so the presenter asked, "in which case, why are you still surprised by it?".
The argument was that, you know these events are liable to happen before you set off, so they shouldn't surprise you, and they argued that surprise is part of the anger. I'm not 100% convinced by the last bit, but I reckon the general point's valid.
However we travel, even on foot, there's a fair chance we'll see someone do something we see as wrong. The rest of it is down to our own mindset.
I've had terrible road rage in the past, including jumping out with an iron bar and ramming another car with mine, but I find a smile, and a wave when people think I've cocked up works far better, even if it was them in the wrong. Getting angry changes nothing but your blood pressure.
On my bike, I ride assertively, but try not to Police other drivers. I just try to get on my way safely and efficiently.
Having said that, not that long ago, on a single track road (or was it a galaxy far, far away) I did just stop plumb in the middle of the road and insisted a car reverse back to the passing place they'd just ignored, so I don't think I've qualified for my orange robes just yet.