h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

*officially claims the right to be the first person to contribute. *

Not much, but... if you're using chopsticks in Japan, it's considered exceptionally rude to spear your food with one chopstick. Also, japanese chopsticks are tapered, and chinese aren't. ((Pretty sure of this, but may be wrong))

*looked and has found some more Chinese rules*

When you've finished, rather than the Western *middle of the plate* method for placement of eating implements, in China, one puts one's chopsticks horizontally on the table or plate.. but in the case of a bowl, NOT on the bowl.

Chopsticks should also not be pointed either upwards, or at people, since this is bad luck.. (similar to the Javanese / Balinese rule of not stepping over musical instruments, since they make a line up to heaven)

As in the West, don't start eating before other people, but don't start clearing the dishes while other people are still eating.

Another Chinese custom... the host routinely places food in other people's dishes for them: so don't give them strange looks if they do this to you. In addition, you can reach for things on the other side of the table, as long as you stand up to do it.

India/Pakistan/Bangladesh/Sri Lanka etc.

Don't use cutlery as the west do. That is what Nan bread and the like are for. So if youwant to truely experience curry throw away the knife and fork and use your fingers and bread.

You mean you're not meant to just do that anyway? *scratches head*... so that's where I've been going wrong all these years. Wondered why I always get so many strange looks.

One last bit for Japan and chopsticks: if you've got a bowl full of rice, never stick the chopsticks down in it and leave them standing there. In a full bowl of rice, you could do this and have the chopsticks be held up "on their own" (by the rice in the bowl), but you don't do this because this is how rice is offered to the dead.