The title says it all. I know it means 'bad faith' but I'm really looking for a more concrete explanation of what it means and how it relates to ethics. Additionally, it would be helpful to understand the existing theories about why it exists in the human condition.
It's specifically a concept from the French existentialist work of Sartre and de Beauvoir, and refers to the unwillingess of people to take responsibility for their choices and the self they create through their actions. It's difficult and frightening to admit we make our own choices, so we invent reasons to justify ourselves. In Sartrean ethics you have absolute responsibility for yourself and the world around you, a responsibility that is in no way diminished by sharing it.