1. Do not slice rolls with a knife.
A bread roll is not a sandwich, for goodness' sake. Tear off a bite-size piece of bread with your fingers and butter it with a knife.
2. Don't leave your spoon in your soup bowl.
Use your soup spoon to scoop from the side of the bowl furthest from you and sip from the side of the spoon that faces you. In between sips and after finishing your soup, rest your spoon on the soup plate beneath your bowl.
3. Don't use your spoon when you're twirling pasta with your fork.
First of all, a formal dinner would never serve spaghetti. Next, know that you should use only a fork to twirl your noodles. Using a spoon to help out is an American custom, which is not practiced in Italian and other European households.
4. Don't pour milk after your tea.
Pouring milk into a cup before the tea is what the British and, well, science dictates. Pouring the milk into boiling water afterward causes the milk to heat up unevenly. This will affect the outcome of the milk, causing it to clump and change the taste and skin on the surface.
5. Don't forget to tap the table.
In a Chinese setup, you must tap the table with your index and middle finger whenever your teacup is refilled, as a way of thanking the pourer.
6. Don’t swallow your raw oyster whole.
Take the fork with three prongs, and gently detach the oyster from its shell by moving it around. Pick up your shell and tilt it toward your mouth from the wide end. Give it a chew once or twice to get the flavors out.
7. Don't eat your Korean banchan (side dishes) as a main course.
In Korea, banchan is communal so all members of the family are meant to share these tiny portions. These small plates are not main courses. In restaurants, you are encouraged to order extra banchan but discouraged to hoard them on your plate. Take these before the meal and together with the main course.
8. Don't ask for rice with your main courses.
The Chinese believe that the flavors of the main dishes are meant to be enjoyed and should fill the stomachs of diners first. This is why heavy and filling rice is served usually before dessert, so don’t demand your fried rice any earlier. An informal restaurant, however, serves the rice together with the main dishes.
9. Don't mix soy sauce and wasabi.
Wasabi, especially the fresh variety, is meant to be savored. When you mix wasabi into your soy sauce, you are actually diluting its zest. When eating sashimi, you can place a dollop of wasabi on the slice of seafood and then dip it into the soy sauce to relish its tang. For sushi, sushi chefs have already prepared a portion of wasabi between the “shari” (rice) and “neta.” Remember, when you do dip the sushi into soy sauce, do it with the seafood-side down.
10. Do not devour xiao long bao in one go.
It isn’t sushi and you would not want to get burnt by the scalding broth packed inside. To avoid burning your tongue, some restaurants provide bigger spoons so you can take a bite and let the soup run along the side so you can sip it. Otherwise, it is suggested that you nibble on the top and give it a few seconds to cool before drinking the soup.