Manners, such as saying 'please' or chewing with your mouth closed can be thought of as daily practice of self-control. Posited by Norbert Elias, the idea of manners in a culture came into fruition because of the rise of democracy.

When there is pressure from the culture itself to exercise restraint and self-control, there are all kinds of structures that can emerge (Aggressive gameplay earns big rewards) from that need. In this case, "good mannerisms" were the system that developed to keep foresight and good will in check.