Some rules for phone users.

Things you can do:
-Wear your phone when you're out.
-Call back someone later or send a message if he/she didn't answered you before.
-Turn off your mobile phone if you don't want to recive any calls.
-Repeat what you said if someone didn't hear you, but call back is better.
Things you shouldn't do:
-Take calls when you're crossing a street.
-Interrupt a face-to-face conversation to take a call.
-Call people back late at night.
-Use your phone in hospitals.
-Keep your mobile phone on during family dinners.
-Leave long voicemail messages.