The staines massiv that seem to always be there (typically age 12-13). Where are their parents...
People who smoke in queue lines, seems a regular thing.
Younguns at fright nights who go overboard with being fake scared (e.g. screaming at nothing). Once in Se7en the actor had to come out of character to tell a 'lad' group of young teenagers in our group to calm down, didn't really add to our scare experience...
Not really an annoyance but people who, when the ride arrives back to the station, don't undo the seatbelt so as the restraint lifts they are left stuck for a bit. There's always one.
Anyone who likes DBGT