I think the most frustrating one is "Is there something wrong with X?" without any accompanying details. That's not a helpful question at all. What part of X isn't working? Is the server not responding? Are you pressing a button and it's not doing anything? Are you pressing a button and getting an error message? Are you loading the page and seeing something unexpected?

Followed closely by the aggravating design critique/question, "Can't you just make the page pop or something?"