For me, the most interesting part of the experiment was how it was ended. A moral person objected. That's a real lesson in leadership.
Wikipedia: "Zimbardo aborted the experiment early when Christina Maslach, a graduate student in psychology whom he was dating (and later married),[14] objected to the conditions of the prison after she was introduced to the experiment to conduct interviews. Zimbardo noted that, of more than fifty people who had observed the experiment, Maslach was the only one who questioned its morality."