
Perhaps the most charming custom the foreign traveler to Thailand encounters is the wai, the prayer-like placing together of the hands, usually accompanied by a slight bowing of the head. It gives one the immediate sense of having landed in an exotic culture. Guide books provide perfunctory explanations of how the wai is used. It is a natural reaction of visitors encountering their first wais to reciprocate and, somewhat self-consciously, return the gesture, but it's not always the proper thing to do. The protocols are complex and they take a bit of getting used to.
The basics are simple enough:
1. Younger people wai elders upon greeting and a wai back from an elder is optional. Often, a smile and a slight bow is the returned gesture. It is considered very bad luck (seven years bad luck) for the younger person, if an elder wais someone younger first and Thais are super superstitious, so don't wai a younger person first (unless he's a monk, or an authority - I'll get to that).
Now, ya gotta love it... I mean... You want to manage a social system of respect through rewards? Easy - attach superstitions. Respect for your elders? Seven years bad luck if you don't. I don't know the prevailing thinking on this now, but there was a time when some Buddhists believed that only men could achieve nirvana, so women were encouraged to treat men very well in order to make merit and increase their chances of being reincarnated as men in their next life. It seems us men will dream up almost anything to maintain a hedonist lifestyle and keep the gender edge.
But I'm off the track. Back to the wai and wai not.
2. You should never wai anyone who you are paying for service, such as waiters, tailors, vendors, shopkeepers or taxi drivers (it makes you look a bit silly), but they will almost always wai you, as a sign of gratitude for your patronage. A returned nod will do. You also wouldn't wai your peers and friends, but when leaving a party, or other such gathering, you should wai everyone, as this is the polite way to excuse yourself.
3. Social status is indicated by the height of your wai and depth of your bow. There are different kinds of wais. The normal wai is with your hands pressed together at about chest level, presenting a slight bow with your body. The wai to a superior is with the tips of your fingers at nose level, still bowing your body. To convey the most respect and gratitude, you will wai with your fingertips at mouth level and present a deeper and longer bow.
Note: It's extremely difficult for a left-of-center westerner to adapt to the social status thing, so we tend to wai willy-nilly when we first get here and probably look ridiculous to the Thai eye. On the other hand, it's a better-than-nice feeling to receive respect simply because one has managed to live a long life (no matter how screwed up it may have been).
4. Always wai monks. Monks wai no one, not even the revered King. If you are receiving a gift from someone, wai before reaching for the gift (age doesn't matter when it comes to gifts). Wai immigration officials and other authorities.
4. Always wai monks. Monks wai no one, not even the revered King. If you are receiving a gift from someone, wai before reaching for the gift (age doesn't matter when it comes to gifts). Wai immigration officials and other authorities.
(I was the only expat in our recent visa run group to wai the immigration officer when he stamped my passport. He was obviously pleased that I understood the protocol and he scrambled to return my wai, accompanied by a wide smile.)

The wai is a unique, graceful action practiced throughout Thailand. It plays a very important role in showing respect and is central to Thai etiquette.

The shape formed by the hands in making the wai is like the closed lotus bud, which is often offered to the Lord Buddha as a symbol of purity.
Um... perhaps not all wais have pure motives.
Kup Khun Krup
(Thank you for reading this post.)