It goes like this: at a social setting involving food, conversation naturally ebbs and flows between those in one's immediate vicinity at table. As menu choices are made, as the waiter (or waitress) takes food orders, common ground is established; alliances are negotiated. Natural groupings form as people spontaneously find someone else that wants to order the same type of naan (or rice) as them, and short-term food sharing arrangements are instigated.
These apparently simple pacts hide subtle complexities like: who should make the first tear? Does one take an approximate half in one go? Or repeatedly return to the plate, tearing at the bready deliciousness with increasingly stained fingers?
See also: Rice Partner