If that's what's holding you back, don't worry. Thai people are very chill and kind. Also the economy is very dependent on tourism, so dealing with westerners is part of that - it's something people are used to for better and for worse. And, the US has not fucked Thailand over anywhere near as much as the surrounding countries (vietnam & cambodia, mostly, but even those folks are extremely gracious). People will appreciate you if you are kind, polite, and try to follow local customs.