Not having a proper warmup at the beginning of classes, or not cooling down at the end. I don't want to draw attention to myself by stretching etc in the middle of a class, but I'm also not going to put myself at risk of injury/pain.

Teachers with little or no knowledge of middle eastern music or culture - thankfully my current teachers are very good in this respect, but my first teacher only owned one Middle Eastern CD, which she used every week!

Lack of criticism. I know I'm not doing everything perfectly. I want to know how I can improve. This is probably a bit awkward for my teacher as I'm one of the more advanced students in her class at the moment and I think she might be worried about also intimidating other people if she criticises me a lot, or something. But I think she also takes a general approach of letting people do things 'in their own way' as long as it is safe and doesn't look awful, which sometimes bothers me slightly. It's possibly OK to let beginners do whichever variation of a move they find easiest until they have mastered it, but at an intermediate level I don't just want to be able to do a move in one way! I want to be able to master different variations and nuances, and 'just do it in whichever way works for you' can be fairly frustrating.

And related to my last complaint, just because you aren't a beginner any more doesn't mean teachers should forget about posture. Posture makes a huge difference to how dancing looks, and I feel that a teacher should be always telling students how they can continue to improve their posture, arm positions etc.