oldgirl2 I saw the same situation in Copenhagen and also in The Netherlands where we had a cycling holiday with our twins some years ago. I think the clearly separate tracks, most of them separated by kerbs, and the separate sets of traffic lights for cyclists really helps. The narrow, busy roads of the UK just wind everyone up.
What was also different though, especially in the Netherlands, was a notable courtesy extended to everyone so motorists would not only slow down on roundabouts where cyclists have right of way over cars, but they would do it in a way that was calm and polite, they were looking out for us. Occasionally, motorists stopped when they didn't need to and waved us across. The pace of cycling was also slower in general and no one wore helmets or hi-viz or lycra. It felt very human sized.
Why do we get so annoyed with other road users? Cyclists do the same as some have posted. Me too, all those texting and phoning drivers, the ones who pull out without looking, squash us into the kerb, fling open car doors in our face and then say it's our fault, get annoyed if we 'hold them up'. It's depressing as well as stressful and dangerous.