Here are two quotations from my tradition for your consideration and comments. Please add to this discussion by posting quotes from your heritage, culture, and original thoughts.
Be the master of your will, and a slave to your conscience. (Chassidic Saying).
What restrains beasts from doing harm is something external - a bridle or a bit; but humans restraints lie within ourselves. Maimonides (Rambam) from his Commentary on the Mishnah.
The difference between a sociopath and a safely functioning member of society is the dichotomy of ego-centric versus socio-centric behavior. Our internal restrains keep us clean and green. Their lack creates problems for everyone.
Individuals, as societies without a conscience do the unconscionable.