Apologize

Though you hated her, it is the end of the day, and you really didn't feel like causing trouble. You apologize sincerely (though you didn't do anything wrong). She listens for a moment and then scoffs at you, turning away to talk to her friends. Now that's a really bitchy move.
Anger builds up and you fight against temptation to beat the shit out of her. You stand there for few moments, trying to control your anger.