I haven't got used to the Indian head shake. Is it yes? Is it no? Is it maybe?
Another confusing time is asking for directions. For example, 'Where's the Kutch Museum?'
I get a twisted hand movement that vaguely points in a direction. So I point in the direction that I think they mean but off course I don't get the headshake. So I feel that asking for directions isn't that helpful.
Here's an interesting link on Indians, though it doesn't answer the above.