Car drivers who sat in a sideroad, appear to notice me coming along on motorbike, then leave it just til Im within 5 seconds of passing them, then decide to pull out as fast as they possibly can to get ahead, promptly reducing their speed to half the limit as soon as they are in front of me.
Bus and longer vehicle drivers who take roundabouts as some some kind of dominance challenge where they act oblivious of other people using the roundabout, veer widely across 3 or 4 lanes with no apparent warning, indication or awareness.
Bikers who switch lane 6 times down a duel carriageway with no indication, mainly overtaking straight down the middle and giving us all a shit name.
Pedestrians who seem to either think they are driving some kind of vehicle, or have massively overestimated their running ability, darting out in an attempt to cross the road when your practically level with them, forcing me to slam the brakes on and nearly get crushed by the rubbish truck following me.
Morons who when seeing bikes filtering through heavy traffic, actually make an effort to physically block the path with their car/van/whatever. You chose to buy a fucking car, which means you have to sit in traffic, this isnt a new concept, dont take it out on me cos I thought of this ahead of time.
Any vehicle or road going entity that decides its fine to double or triple up inside a lane. This includes horses, cyclists, walkers, bikers. Particularily on backlanes where there is often low visibility due to hedgerows.
And an extra one for horses that leave shit all over the road, literally. Tripled up on single track roads who then refuse to get out of the fucking way for almost half a mile, despite there being plenty of room and me having kept the bike revs very low so its not like i was gonna be bothering them more than any other road user. Generally cut the thing entirely passing horses, tho tbh if they cant deal with a bit of noise from a passing road user they shouldnt be on the fucking road in the first place.