My staff will randomly reset while working. You can tell because they're in the middle of doing an action, then all of a sudden they're standing as stiff as a board. It's really annoying because they don't ever tend to the dirty tables, then people start complaining that the decor of the restaurant is not satisfactory.
I also noticed that you can't even make a profit until you hit 5 stars. If you don't upgrade your staff's abilities and their wages, then they will either quit, or keep providing lousy service. Makes it difficult to run a humble diner.