15 years ago I worked in a resort in the Rockies for a summer. Asian tour buses came through almost daily. The classification went like this:
Japanese: most polite and clean people you'll ever meet, will go so far as to pick up after themselves even though they're being catered.
Koreans: Much more direct than the Japanese, but no problem.
Chinese: Get out the straws, whoever pulls the short one is on bathroom duty, there's a pretty good chance you're going to have some floor shitters (yes, literally people shitting on the floor in freshly cleaned bathrooms which obviously have private, fully functioning toilet stalls).
Then there's the mouth open chewing, sneezing and coughing with literally zero effort to cover mouth and nose, etc. From my experience, the Chinese have terribly hygiene habits and this most likely also contributes to the way diseases spread in China.