Everyone is an idiot
Everyone is an idiot. Everyone. If you can count on one personality trait that a person will default back to at some point or the other, it would be his/her unique but substantial idiocy. And if the society were to be built on a single rule, it should be about people agreeing that compassion towards others' idiocy is essential for a convivial and pleasant world. What good ever comes from being a cynical, patronizing git, anyways?