Never joke about the monarchy. Thai people treat their monarchy with great reverence and the Royal family should never be insulted or criticised. Buddhism is Thailand's national religion and priests must always receive a high level of respect. Women should never touch a monk or his robe. When handing an object to a monk, a woman should use an intermediary or place the object in a position where it can be retrieved by the monk.
Thai people regard the head as the most precious part of the body.
In the same way, Thais regard the feet as the least sacred part of the body and it is considered offensive to point with the feet or even show the sole of the shoe or foot to another person. It is therefore necessary to take care when crossing your legs. Never accept objects presented to you with your left hand as this is considered disrespectful.