Neighbours who chip away for years instead of hiring power tools to do the job quickly (eg chipping up old concrete)
Posters who sneer at other posters who disagree and assume an air of superiority over those posters they consider intellectually inferior because they voted differently from them.
People who constantly poke at their food on the plate when they haven't even finished the last mouthful! The clashing sound of the cutlery gets on my nerves...