Speaking from personal experience, you might

1. Get additional classes without extra pay

2. Be forced to attend special "lunches" or "dinners" with some supposedly important local government official

3. Get spied on both in your class as well as having visitors come to your home unannounced

4. Be asked to do outside the class activities such as English Corners

5. Be used/exploited by some unscrupulous locals for their own business agendas

6. Deal with characters both local and foreign, but amongst the foreign teacher circle you will always find some pompous know it all who will dump on you.

This isn't something that will necessarily cause trauma in your own mind if it happens occasionally, but over the long haul you might find yourself looking for a new job in china hoping for something better. "Better" is almost impossible though, so you'd best take care of yourself and tread carefully.