Across the globe, there are many cultural differences that define each country. As a traveler, it’s important to educate yourself on what you should and shouldn’t do when visiting a new locale... Here's an interesting article I came across in Huffington Post worth reading...
In India, you should finish everything that is on your plate because it is considered a respect for the served food, and food in India is considered sacred. In South India, where food can be served on a banana leaf, it is polite to fold your leaf over from the top ― not from the bottom, because that indicates you were not satisfied.
The same is true about finishing your plate in Japan. The Japanese consider it rude to leave food on your plate, whether at home or at a restaurant. It’s related to one of the fundamental concepts in Japanese culture, mottainai, which is a feeling of regret at having wasted something.
In China, however, leaving behind an empty plate is a sign to the host that you’re still hungry. If you don’t want to eat more food, consider leaving a little behind to let the host know you have had enough.
Ethiopians don’t even bother with plates. Individual plates are considered wasteful. Folks share meals off of one big communal plate, and generally eat with their hands using injera ― a type of flat bread ― to pick up the food. So, don’t even think about asking for your own plate.