"Just following orders..."
After WWII, the world wondered: How could ordinary Germans participate in the Holocaust? Stanley Milgram tested this at Yale. Participants were told to shock a 'learner' (an actor) for wrong answers. The shocks increased to a lethal 450V. Despite the learner's screams, the experimenter in a lab coat calmly ordered, "The experiment requires that you continue."
Most people predicted fewer than 1% would go to the end. In reality, 65% of participants administered the maximum 450V shock. This proved that ordinary, moral people can commit atrocities when obeying a perceived authority figure. It reveals the terrifying fragility of individual conscience against authority.