China
Beijing and Shanghai are generally pretty miserable, unless you get to know people.
Smaller Chinese places are usually nicer.
Guangzhou is big, but I’ve always found it friendly… sometimes remarkably so.
All market-sellers in China drive “a hard bargain” for foreigners, but if you learn a bit of Chinese, they will be much more friendly, and usually have a bit of fun with you (as you drive the price down by 95%)
I think Beijing & Shanghai, like London and Paris, are disillusioned WRT tourists, and are mostly sick of them (but not their money). I never got to know any middle-classes there though.
Mainlanders outside of China are usually hard to get to know, but generally really good people with strong sense of morals and acceptable behaviour. Still, there is a lot of diversity in the people of China. Perhaps comparable to Europe.
HK is very busy, but street manners are much better than the mainland, and there are plenty of cool people to get to know. still, there are more scammers than your average chinese city (but less than shanghai & beijing).
Vietnam I found to be friendly, especially outside the cities, with locals generally very interested to speak to foreigners and help them, even through the language barrier. No scamming either, though there is petty crime in the big cities.
Cambodia is a very poor place, but the people are usually VERY nice. They are making something out of you, but they’re actually thankful for your patronage, and I never had someone try to scam me. Not the safest place in SE Asia though.
Thailand I can only speak for the area around Khao San Road, which is populated almost exclusively by drug dealers, pimps, prostitutes, dancing girls, sewer rats, and hedonists of various persuasions. I’m a big fan of vice, and even then this place appalled me. Plenty of friendly people to meet at the bars, but the locals here are all out for a buck.
Can’t extrapolate to the whole country, all other Thai people I have met have been very pleasant.
Malaysia was very accommodating too, again happy to see foreigners taking interest in their culture (even as a heathen during ramadan).
Singapore is elitist in the extreme, and people will immediately judge you based on your perceived wealth and degree of sophistication. I arrived after 2 months travelling Asia, with a beard and dirty trousers, and nobody would even look at me. After shaving and scrubbing up, I was treated with a bit more respect, but I didnt have the money to go out and meet locals. The Singaporeans I have met besides that time have all been nice, though predictably straight-edged.
I’ve hear Laos is really friendly, and I’d like to visit there, next time I’m in the area.
At the moment, I live in Japan. People seem impossibly nice. That doesn’t mean they’re open. Japanese are very shy. But they also have a strong sense of public duty. This duality is manifest in the fact that people will compete to pick up the 1 yen coins you dropped on the floor by accident, to return them to you, but will all dither and sweat and deliberate and hesitate with apprehension, if something serious and confusing is happening (like someone experiencing a seizure on a train).
All that said, the overall experience is extremely pleasant, although sometimes honesty would be more welcome than flattery, or ridiculously over-the-top politeness “hiding” disdain.
Suppression of anger and dislike certainly engender a more civil atmosphere though, until you start to take the tiniest possible suggestions as signs that someone may be disrespecting you, or plotting behind your back.
Still, in general I find the Japanese to have a more positive attitude than English people (where whole sections of society hate everything), which is refreshing…