Occasionally, Kim gets out of control and starts poking fun. When someone notices this, she replies, "That's why they call me Mean Bitch Espinoza" and they all understand. When the term is inappropriate or just too long to say, the abbreviation MBE is used.
Sometimes when Kim starts poking fun, her lab section parter asks her, "are you being MBE today?" Usually the answer is yes.
Some examples of Kim being MBE:
Did you hurt yourself? You should be more careful.
I'm not that type of girl, and if I were that type of girl, I wouldn't be that type of girl with you.