A courtesy is a form of polite behavior and excellence of manners. You will find that Navy life creates many situations, not found in civilian life, that require special behavior on your part. Customs and courtesies help make life orderly and are a way of showing respect.
Customs are regular, expected actions. They have been repeated again and again and passed from one generation to the next. Courteous actions show your concern and respect for others. Take some time to show a little courtesy now and then.