There are few more irritating cultural faux pas than doing a Wai wrongly or at the wrong time.
Thais are actually somewhat OK about foreigners making the error, so it’s more a Western perspective on getting it wrong, but if something is worth doing it’s worth doing right, or at least at the right time.
The Wai is when the hands are brought together and the head tilted down. It can be used as a greeting, as a goodbye, as a thank you or as a hierarchical show of respect.
The first rule of the Wai is that older people don’t Wai younger people. It’s a cringe making observation to see the newcomer doing the Wai to their 16 year old waitress in a restaurant or a bar. They mean well but its cultural ignorance not to know this. In situations where people are of a same age its ok for either or neither to Wai each other though if the deferential person wishes to pay their respects to an authority or well respected figure, this is well received.
In general the Westerner should reserve the Wai for older family members and if attempting to put down good cultural and long term roots in Thailand it’s a good idea to Wai one’s respected seniors in a social or business circles.
This is a simple one that few people know about, but is great for bonding with people in one’s neighborhood.
Sawasdi Krub or Ka (depending on whether you are a male or female) is the universal hello and goodbye in Thai but a more informal greeting that could be described as “Hello Mate” is Waddi Kap (or Ka). It’s a variant of the Sawasdi Krub (or Ka) but it’s a good way of showing people you like them and are not just saying hello for politeness reasons.
Thais, particularly local Thais in one’s neighbourhood will appreciate this though as it is more colloquial, try not to use it with respected or important people, though most will still receive it the way it is intended.
Thais place great importance on eating elegantly. We don’t mean eating in elegant surroundings but if with cultured and educated Thais, the way the fork and spoon are handled and the manner in which the food is conveyed from the cutlery towards the mouth will be noticed by quality Thais and is a much more elegant way to eat.
Hold the fork in the right hand and the spoon in the left hand. They should be held so that the smaller fingers are gracefully splayed and the thumb and index finger are pinching the ends of the cutlery with the middle finger acting as a balancing support. Think of pushing the food onto the spoon with the fork as ballet choreography. The aim is to put just the right amount of food onto the spoon and convey it to the mouth in the most genteel way possible.
If unsure about your technique, pay close attention to diners in quality restaurants and hotels. Elegant eating is an important part of a romantic date with an elegant woman.