People who ask what 'this' or that' is, waving their arms about. Like they don't know what an object is called, and it's obviously a hammer, or a sandwich, or some such common place thing. All other such vaguery is equally twinging. Like, "The thing outside is open".
Folks that interrupt then fall short halfway through their sentence, not knowing how to express themselves, but adamantly needing your attention to watch them stammer.
Folks that ask questions, and when you answer reply, "I know". When it is obvious they do not know.
People who say they can do whatever, and when put to task display their lack of ability, costing me time, money, and effort. Better to say "I'll try" or "I haven't done that before" than to claim proficiency and prove inadequacy.
Pointless acts of violence or poor behavior to make one's self feel better about themselves.
My failure to overcome those and other 'peeves'. That's the worst!