Thai police, viewed negatively by some, are in general pretty nice and friendly. The main thing to keep in mind when dealing with police is to be polite and respectful.
If you know some Thai, make sure to sprinkle lots of polite sentence endings into your speech. If you don't know any Thai, keep your voice down, smile (don't smirk) and use simple English words that will probably be understood, for example: "I'm sorry", "I don't know", "Please help me."
Some foreigners think they are singled out because they are foreigners. Some Thais think foreigners get away with a lot because they are foreigners. The truth probably shades over toward what the Thais think.
First, most police don't speak English too well and don't want to deal with explaining something to someone who doesn't speak Thai.
Second, most Thais are concerned about the image of Thailand, and even if someone has done something wrong, like running a stop sign, the police will frequently let foreigners off with a warning.
Another important thing to keep in mind is to remain calm. Getting agitated will do no good whatsoever. This is especially true if you have to go to the police station. This can happen, for example, if you have a fender bender with another car and can't agree on whose fault it is.
- Do not get frustrated if you aren't understood
- Do not raise your voice
- Do not be sarcastic
- Do not get angry or agitated
- Do not get impatient if you have to wait
- Do not be rude