Recently I mentioned the near-universal modern Chinese belief that a mobile phone, when ringing, should take precedence over anything else that might be going on -- in particular, the person you are talking or dining with at that moment. From a reader, the cross-cultural angle:

The mobile phone versus face-to-face thing is the norm in India as well, and again, is not considered rude or even unusual by the locals. I attended a family wedding in New Delhi a couple of years ago, and the priest took several calls during the ceremony. Taking our cue from the bride's parents, everybody paused while he took each call, and then resumed as if [nothing had happened]. Apparently another priest had failed to show up at a wedding across town, and that family were ringing round all the possibles...

This is one of the few India-China similarities I have come across.