1. The auditory stench of having to listen to one side of another person's cell phone conversation.
2. The painful, grating, and taxing sound of a thoughtless an inconsiderate narcissistic cell phone-talking douchebag.
There is something about the wiring in the human brain that makes it unable to tune out just one side of a conversation. This makes a cell phart an unbearable odor, like when the neighborhood bully holds down a kid and blasts wind on his face.