Since I'm just now getting back into cycling but have been a cager for just over 30 years, I can say without any question that the thing that got under my collar about cyclists the most was taking the lane and slowing up traffic. There's just no question of it. Running stop signs/lights...fine, no hi-viz...no problem...block off roads for a race, no biggie. I could care less about anything they did until it came to slowing me (and everybody else) down. AND ESPECIALLY WHEN THERE'S A PERFECTLY GOOD MUP RUNNING ALONG THE SAME ROAD!!!!! AAAAAAAAGHHHHH!!!! I've done all of the things to cyclists that I see on this board on one occasion or another. (well most) Why??? Because it's just rude slow down traffic while you poke along at 20 mph or lower. As a recent "cager only" I think that's got to be number 1 reason for the hate. It certainly was for mine. YMMV.