I don't necessarily get annoyed--it doesn't make sense to design your whole life around working with beginners and then be annoyed when they don't do things like developed performers--but there are a few things I notice that are easy to fix. 1) Dancing on top of their clothes; they need to leave their clothes at the back or side of the stage, not in the middle of it. 2) Not knowing how to get out of a garment onstage in a way that suggests they didn't rehearse and didn't know that was going to happen, like having a tight dress pull on a shimmy belt. 3) Not finishing the song. This, I admit, is a bit of a peeve. Walking off waving and hoping the DJ sees you leaving and stops the song for you isn't a strong ending.