The document discusses common courtesy and how it involves respecting oneself and others. It states that if you cannot respect yourself, you cannot respect others. The purpose of courtesy is to be unselfish and considerate of others, while lacking courtesy means being selfish. Demonstrating courtesy toward others makes one feel good, shows maturity, builds trust, and aligns with the golden rule of treating others as you wish to be treated. Examples of courtesy include handshakes, polite phrases like "please" and "thank you", and holding doors for others.