I got a mountain bike, up to then no suspension, I can hear a vehicle behind me, and can see the pot hole in front, know I can't avoid it, and worried about wobble as I hit it, but no need to worry, hardly knew it was there. Bikes have improved, but not all bikes, and it is human nature to think every one is like yours, and is as steady, but they are not, OK at 10 MPH steady, but up hill pushing hard at 3 MPH and the wobble factor is greatly increased.
I however when rounding a corner and seeing a cyclist have to consider 3 options, one brake hard, and some one may run into me, pass on other side of road which is norm, or squeeze past, which is rare, with a tractor maybe same speed as cyclist I can see it over hedge rows well in advance, and he is taking up whole carriageway, so you see as soon as you start to go around a corner, but the cyclist is into hedge so further around the corner before you see him, even the main roads here only just wide enough, so it is simply not safe.
Narrow lanes are worse, if road is 4 meters wide then clearly if the vehicle is 2.6 meters wide you can never give 1.5 meters for cyclist, all well and good in a City with wide multi lane roads, but I don't live in a City. Often I simply can't pass until cyclist stops and pulls into a gateway. Even then crawling past with him nearly touching the car.