What's bad about bad faith?

Contemporary common sense holds that authenticity is an ethical ideal: that there is something bad about inauthenticity, and something good about authenticity. Here we criticize the view that authenticity is bad because it detracts from the wellbeing of the inauthentic person, and propose an alternative moral account of the badness of inauthenticity, based on the idea that inauthentic behaviour is potentially misleading.