There are times when you should never answer your mobile phone. Movie theatres, plays, and restaurants have no place for mobile phones. Even more so, mobile phones should be left in the car when you visit mosques and funeral homes. At the very best, they should be on the vibrate setting during these times.
If for any reason you do receive a phone call in one of these places, do not answer the phone. Discreetly check the number to see who has called. If you think it may be an emergency, excuse yourself and return the call once you have stepped outside.