Line cutters and people taking lots of flash photography where it is not allowed. I also HATE it when I see other park guests being rude to each other....and most especially cast members. I try very hard to be annoyed and move on quickly. I don't want to waste my vacation time being crabby.
I got some really interesting pet peeves and witnessed some 'lively debate" on this thread. At some point in the near future I'll ty and post a summary of the pet peeves. In the meantime, I opened a new thread for folks to tell positive stories as they relate to Disney trips.