Consider the enormous amount of time that is wasted by being rude. Rudeness gets in the way of effective communication. It makes things difficult, expensive and time-consuming for everyone involved. It is really easier, less costly, and less stressful to be courteous and polite.
Being courteous does not mean being a wimp. You can be very firm with someone and still be courteous. In fact, courtesy comes from a position of power. People who are rude, usually act that way out of a lack of confidence. Rudeness is a strategy of last resort, an act of desperation, and an admission of weakness. Rudeness comes when we are simply unable to adequately express ourselves.
Courtesy is strong and powerful. It is effective. If you are courteous toward someone, and you receive rudeness in return, you have won — you are clearly superior by the admission of both parties. If you are able, through your courtesy, to diffuse the rudeness of another, you both win.
Being courteous is a decision, not a reaction. It is not enough to be courteous only when someone is first courteous to you. What if everyone did that? No one would ever get the ball rolling. Courtesy requires a leap of faith. You must have enough faith and confidence in yourself, and often a certain amount of detachment, in order to initiate courteous behavior.
And if your courtesy is met with indifference or even rudeness, so what? You haven’t lost anything. There is no downside to courteous behavior, yet the upside potential is enormous.