I've been to several Asian countries, I go to the Philippines for at least 2 weeks a year. My personal experience is that American customs and immigration are about the rudest there are. In China, everyone hates the Chinese Government, right? the immigration people are very polite and courteous, same with Japan, Taiwan, South Korea and Taipei, I might have missed one or two, but you get the point. My first time back to Seattle from overseas was a fucking rude awakeining, I was disgusted by the attitudes of the customs people and TSA, I almost got arrested for putting a verbal smackdown on a TSA clown for being rude to a little old Japanese lady, he was harrasing her, doing the loud slow talk that makes everyone in the world understand english, and I told him that shit doesn't work and maybe an interpreter would be a good idea and if he needed any more common sense ideas to go ahead ask, I'd only charge a nominal fee.