30 Phil, Chapter 31, Sartre, Touchstone 80: Bad Faith.

Bad faith is the idea of living a lie; it is the act of denying your inherent freedom and responsibility associated with self-awareness. When you go along to get along, you are not yourself, you are being a rock, you are a “being-in-itself.” To live for yourself means your become your authentic self, you then are a “being-for-itself.”