phone etiquette

Call me the Miss Manners of Mobility if you want, but I believe in cell phone etiquette. What is etiquette, anyway? It's really nothing more than a set of rules we all agree to follow in order to be considerate toward others. We follow them as our contribution to the kind of society we want to live in. It's easy to be rude with a cell phone. A visitor from another planet might conclude that rudeness is a cell phone's main purpose. Random, annoying ring tones go off unexpectedly. People talk too loudly on cell phones in public because of the challenge of holding a conversation in a noisy environment with someone who's not present. Cell phones need their own rules of etiquette, or we'll descend into social barbarism.  What happened of someone returning calls or messages??? Well, i understand that one may be busy so may not be available to answer the call..or may have left the phone either at home, in the car or in the office. What i dont understand is why one cant be courteous enough to reply or to return the call!! Its very annoying  and i think its about time that people learn the art of phone etiquette!!! it doesnt require as much