I can't stand certain repetitious noises. Someone tapping a pen, or drumming their fingernails on a table, a phone ringing non-stop (even if it happens in a movie), yet certain other noises that are repetitious don't bother me. The sound of my fish tank filters don't bother me a bit. I find them comforting. If someone honks a car horn more than once, waiting for someone to come out of a house on my street, it infuriates me. Sometimes, even if a car drives down our dirt road, it irritates me to the point of anger. And bagpipes--they drive me insane! My mother was the same way, so I'm sure it must be inherited.