Religion
Almost equally insensitive would be to disregard certain religious precepts.
Buddhism plays an essential part in the lives of most Thais, and Buddhist monuments should be treated with respect – which basically means wearing long trousers or knee-length skirts, covering your arms and removing your shoes whenever you visit one.
All Buddha images are sacred, however small, tacky or ruined, and should never be used as a backdrop for a portrait photo, clambered over, placed in a position of inferiority or treated in any manner that could be construed as disrespectful. In an attempt to prevent foreigners from committing any kind of transgression the government requires a special licence for all Buddha statues exported from the country. With the above in mind, there is however no need to worry about taking photos of Buddha images or temples, inside and out. So long as it's tasteful in their eyes.
Monks come only just beneath the monarchy in the social hierarchy, and they too are addressed and discussed in a special language. If there's a monk around, he'll always get a seat on the bus, usually right at the back. Theoretically, monks are forbidden to have any close contact with women, which means, as a female, you mustn't sit or stand next to a monk, or even brush against his robes; if it's essential to pass him something, put the object down so that he can then pick it up – never hand it over directly. They're also forbidden to touch money (must put it in an envelope first), alcohol and cigarettes/narcotics. Nuns, however, get treated like ordinary women.