I think my biggest annoyance is 'inconsideration'; I can tolerate a close pass but it really annoys me when they didn't need to (outside lane was empty), likewise SMIDBL (Sorry Mate I Didn't Bother Looking) annoy me, or the 'its only a bike' brigade !
Sheep really anoy me too (not the wooly kind

); folk who assume as it was clear for the first driver so it must be clear for them!
I think next on the ever extending list, would be 'must overtake cyclist' autobots, only to do so and find they can't go any where and slam on their brakes block/ my path.
The indicator thing used to annoy me more but folk use them that wrong or not at all, I tend to ignore them these days. It still a bit irritating however, when something comes towards me on a roundabout only to leave at the exit before my entry and doesn't indicate.