People usually do not shake hands when greeting. Instead, the custom is to “wai”. Usually the younger person “wais” the older person by placing his/her palms together and bowing slightly. If the hands are high, the person is greatly respected. The older person then returns the gesture. This greeting is done while standing, sitting or even walking. If someone does not offer you a “wai” (especially if you are a foreigner) then it is polite to offer a handshake. Smile and bow your head out of respect. A wai can mean “Hello”, “Thank you”, “I’m sorry”, or “Goodbye”. A wai is not used to greet children, servants, street vendors or laborers. Never return a wai to a child, waiter, clerk, etc. Simply nod and smile in response. Monks do not return a wai.
If invited to a Thai home, a gift is appreciated but not required. The gift should be wrapped. Gold and yellow are considered royal colors so they are good choices for wrapping paper. Appropriate gifts are flowers, chocolates or fruit. Silverware is used, as well as chopsticks for noodles.
Sticky rice, a Thai favorite is often eaten with the fingers of the right hand. It is polite to leave a little food on your plate to show that you are full. If your plate is cleaned, then the host/hostess will think you are still hungry. It is also polite to never leave rice on your plate as this is seen to be wasteful. As in most other countries, it is not polite to ask for a second helping or to take the last bite form the serving bowl. It is also not polite to lick your fingers.
When entering a doorway of a house, you should step over the threshold, not on it. Thais believe a spirit lives in the threshold. You should also remember to take off your shoes out of respect before entering a home, temple or building that has a Buddha image.
It is not polite to show affection in public. You should never touch or pass anything over anyone’s head. The head is considered sacred in Thailand and must be respected.
You should never point your feet at anyone or use your feet to move anything or touch anyone. Feet are regarded as unclean. It is not polite to keep your hands in your pocket when someone is talking to you or to put your arm over the back of a chair in which someone is sitting. It is not polite to wave your hands when you talk or to pass anything with your left hand. You should not point with your fingers or your hands. It is not respectful to cross your legs when older people or monks are around. If you want to get someone’s attention, you should hold out your arm with the palm of your hand down and flutter your fingers up and down.