"Bonbon". Probably the stupidest word ever to enter the English language. I get chills when I hear it.
Edit: Also "debut." That word sounds really annoying in any sentence to me. I really have a lot of words that bug me, but I can't think of many at teh moment. I sometimes have to ask people (half joking, half serious) "Please don't use that word ever again" [img]i/expressions/face-icon-small-tongue.gif[/img]