Your duty as a cell phone user
If you own a cell phone and your ringtone is anything other than a pleasant, quiet ring, it is your duty to keep the phone on you at all times. To leave your phone anywhere else is to subject the rest of us to repeated iterations of Little Brown Jug. Nobody wants to hear your midi rendition of the CanCan. Nobody cares that you spent $1.99 on Pachelbel’s Canon.
Followup: When you get back to your phone, don’t look at the screen and proclaim, “oh, I missed a call.” Everybody knows you missed a call. Everybody knows because we all just listened to your ringtone 7 times.