My wife gets wrong numbers on hers. She carefully explains that this isn't the right number. Then the callers pushes "redial" and she's not as pleasant.

Mine is alwasy turned off in church, in medical facilities, in concerts, and in other inappropriate places -- even though it vibrates rather than "rings." If I must make a call while driving (or if I receive a call when driving) I pull over and stop -- I want to die with my boots on, not my seat belt.