It's important to remember that Japanese are picky about manners regarding the table. Unlike in America, it is highly frowned upon to waste any food. When at a restaurant, it's best to be sure you'll eat everything on your plate before you get it. Table manners, expressing thanks, and appreciation for a meal are extremely important, because to the Japanese, you are lucky to have every meal you get. Food in Japan is in general a lot more healthy, and therefore considered more precious.