I was annoyed reading this. Until I got to the part about her telling you how to wear your hair, and now I’m just angry. I know this may be diffcult, especially in a work setting, but you need to assert yourself. This girl obviously has issues with control, which you did state. The problem is that people can’t bend for her, and that means you, too. If you decide where you’re going for lunch.. then you stick with that. If she wants to argue, you should tell her that she is welcome to join you where you’re going, but otherwise you’ll go without her. Don’t reward her bad behaviour by doing what she wants. That only makes her more likely to do the same thing to you again repeatedly. It is NOT you, it is definitely her.