- point at people or things with your feet. This is considered as highly impolite, as the feet are considered as the most inferior parts of the human body. And do not sit on the floor of a Temple with your feet pointing at the Buddha Image!
- touch the heads of children, even if you may see this as a form of caressing. The head is considered as the most superior part of the body, and touching this part is not a privilege for foreigners!
- be too familiar in public, even if you are married. So don't kiss in public, don't walk with your arms around each other. These things are considered very impolite in Thailand.
- shout in public (to anybody). If you want to argue with your wife or with your children, do this in the privacy of your hotel room and not in public! You will loose much of your respect if you do things like this in public. You will -for the same reason- loose much of your respect if you find you should punish your children in public.
- think that Thai women are "easily available". Though around 1% of the female population is working in the sex industry, this also means that 99% is not working there! You can get yourself in big trouble if you offend a woman in this way. Her husband may find he should take revenge, which could be very unpleasant for you.
- take any packages through Thai customs for anybody! If you are caught carrying drugs, you risk the death penalty or life in prison. And prisons in Thailand are not exactly like the Hilton. Apart from that, you can hardly expect a milder punishment than life in prison. So be warned!
- buy any precious stones on the streets. If you are familiar with prices, do buy them in (large) shops. That will normally be safe, but -again- be sure you don't pay too much. If you buy precious stones in the street against this advice and regret it afterwards (which will be the case in 99% of the cases), go to the Tourist Police! They know how to handle this and they do it well. (Or call 1699 for the Tourist Police)
- accept any offers from strangers to assist you in finding the right places to do your shopping. They will get a commission from the shops they take you to and you will be the person who pays for that commission (in the price you pay).
- accept any introduction to participate in any form of gambling. Gambling is against the law in Thailand and penalties are severe!
- get involved in prostitution in Thailand. You do not only put your health at serious risk, but the chance of getting robbed is very real. And apart from these dangers for yourself, give it a thought that having "budget" sex in a developing country like Thailand is very unfair towards the people involved.
- buy bus, tickets from anyone, except a bus terminal. The bus you pay for elsewhere might never be leaving or in the best case you will pay too much. If you use a Travel Agency for tickets (or other services), make sure they are licensed by the Tourism Authority of Thailand (TAT). Of course the Travel Agencies in hotels can be trusted and are licensed.
- call a waiter or waitress with the fingers of your hand pointing upward. This is considered to be very impolite. (It will make a similar impression as if you put your middle finger up to somebody at home). Put your hand up, but with your fingers pointing downward (or make a fist, if you prefer that or if you don't understand what I mean here).
- finish the dishes when you are having dinner with Thai friends in a restaurant. Your Thai friends will keep ordering more, until you leave something on the dishes, so that they can clearly see that you have had enough!