The best way I've ever heard lighting design described:
A girl who primarily acts but is running sound for a show, listening to me program for my friend, is asked what is going on during a hold:
“From what I understand they don’t like what they see, and they’re fixing it by shouting numbers at each other.”
When one of your actors who is a music major (NOT theatre or musical theatre) keeps interrupting the run throughs to talk to the pianist half way through his song to make things “perfect”, leaving everyone on stage waiting for him, sometimes for over 7 min. Then, when you lose your patience and ask him to move on and figure it out later this week during Sitz Prob, he snaps at you and makes you so irritated you have to walk away for a moment.