1. Dining
I list this one first because it is absolutely different between both countries. First of all, in Thailand, usually we mainly use spoon and fork to grab the food, but in US, we usually use only fork. Secondly, gratuity or tip in US is relatively high compare to Thailand. In general, it is a good manner to provide around 15-20% on tip depend on the quality of service in US but in Thailand we rarely give tip. But please do not think that Thai people are stingy, this is just because of the different culture :p The last one comes from my observation. Usually American call their waiters by using their eyes. The waiters will know directly that their customers need something. In contrast, Thai people just waive their hands and call for the service.