Terminal Bitch Face
When a woman, despite her mood, always looks bitchy. She might feel cheerful, amused, enraptured, or content, but she always looks like a bitch. Often times the woman is well aware of her condition, and despises how other people constantly tell her to smile. This might actually make her feel like bitching at you. Terminal Bitch Face sufferers often hear "That's just how her face is."
The character Betty Draper from Mad Men suffers from Terminal Bitch Face.