If you're in a public place where other people have to listen to what's going on (the theater, a play, live televised press conference) and you don't understand how to turn your phone's ringer off then maybe you shouldn't carry a phone with you everywhere you self-important twats.
if you're trying to make a presentation and a cell phone rings then maybe you should continue your presentation with as little time wasted as possible.
there's nothing worse than some phone ringing in a class and the teacher deciding that we would all be well-served by a few minutes of histrionic scolding, while the mortified student desperately fumbles to shut it off
Y'all would shit yourselves in China or India, where incoming cell phone calls take precedence over everything, apparently. Even if you're the speaker!