Personally I consider them to be the most polite people on the face of the planet.
It is truly the land of smiles. Sure, perhaps they are smiling because they are just looking at you as you speak in a language, that they don't understand. But, they keep on smiling! A lot of them are very poor people, but they are also a happy people. They're English is not the best (but neither is my Thai) They will smile and say "yes", when they have no idea what you've just said.
But, the smiling is contagious. Get on a plane and go visit them. You'll be glad that you did.
But you'll also have to also consider that you will pay more than a Thai national for just about everything. To get into a National Park, when you buy things, tuk tuk rides. It's basically endorsed by the government. Since the Foreigner price to get into a National Park is 300 Baht for instance, but the Thai person with you pays only 50 Baht. That mindset has carried throughout the nation. They have no problem charging more for you than for a Thai national. I do whatever I can do to just say no,
I want the Thai price, or, I'll have a Thai person purchase something for me, which will save me three dollars. Because that three dollars you're forced to pay every time ads up.