Karen

A white 40-year-old woman who dramatically breaks down when the slightest inconvenience happens.
Usually has an unstylish short blonde bob haircut.

When provoked, she will do one of these three things:

--Collapse onto the ground, crying or screaming
--Demand to speak to the manager
--Tell you what you can and can't do, even if it's not a rule

Cashier: "I'm sorry, our Ice-Cream machine is broken at the mome-"
Karen: "EXCUSE ME, your machine was working perfectly fine yesterday!"
Cashier: "Madam, it broke down yesterday, would you like anything else?"
Karen: "I want to speak to your manager!"