From Aeon: Contrary to the beliefs of many great philosophers, wrongdoing is not primarily motivated by self-interest and greed, but by the desire to fit in.
“Although most assume that an immoral person is one who’s ready to defy law and convention to get what they want, I think the inverse is often true. Immorality is frequently motivated by a readiness to conform to law and convention in opposition to our own values. In these cases, it’s not that we care too little about others; it’s that we care too much. More specifically, we care too much about how we stack up in the eyes of others.”