The Vietnamese love to be hospitable and will often invite you to dinner. If gifts are taken for the family, they should be items that they could not easily obtain themselves.
To take something that they could buy easily would be a bad reflection on their economic means. They love anything from western countries, and it does not have to be expensive. If you give the children things, each should have a separate gift. It is not polite to take a whole bag of candy and give it to them as a group.
On short visits, drink the tea that is offered, even if you don’t like it and are afraid of the local water. It shows that you are welcome and well respected.
Rank is always carefully observed by the Vietnamese in their homes and elsewhere. Servants never sit at the same table with their employers if outsiders are present, and only in rare cases otherwise.
On some occasions at an informal meal, the whole family except for the person inviting you to dinner, may get up from the table and eat elsewhere. This is not a show of disrespect for you but is simply a way of letting the guest spend time with his special friend.
At banquets, one should arrive on time and greet elderly persons first. If the dinner is served Chinese style, food should be transferred from the main bowl to your individual bowl before eating. It is impolite to eat anything with your chopsticks directly from the serving bowl. A guest may refrain from taking something he doesn’t like, but if the hostess serves it to you unknowingly, force it down if at all possible. If the guest refuses, the host may doubt his sincerity and coax him even more. Individual bowls are usually changed with each course and are generally removed only when empty, except the last course. Here, a little something should be left to indicate to the host that there was enough food and everyone is satisfied.