Having traveled and worked in China since 2004 there are certain differences between the cultures. I learned to appreciate those differences without saying there wrong and I’m right.
Chinese philosophy is “never let them get the first step”. They take that in their marketing of products too, the first one to the market has a big advantage. I have negotiated many multi million contracts. The Chinese are tough negotiators; almost everything is negotiable, even drink from a vendor on the Bund.

In China if you 1 in million there are 1300 people exactly like you- a huge population. A survival of the fittest. Chinese save up to 50% their income for bad days of the future. (95 % of cars are bought with cash in China, while in the USA it the reverse).
Normally, Chinese if the queue is short they will wait their turn, if long they will be more aggressive.
Having gone to the Chinese Expo this spring I was queued in lines that were allowed to move up about 100 feet at time to the next pen, the wait was hours. To my experience the pavilion was not worth the hassle but for my friend it was a big deal she wanted to say she went there. She was conditioned for the day.
If you ever travel the Chinese train system you will see people waiting and pushing for the gate to open to get to the platform, not only the train.
Regarding hygiene, their fine restaurants which I visited sometimes did not have a sit down toilet only a squat hole.
Bathrooms on ferries almost made me puke from the smell, to the Chinese it were normal. I was lucky to travel some very non-tourist parts in China, it is not Disneyland, but I was not interested in seeing Disney. I wanted to experience the people and places of real China. I have appreciated these differences.

1/2: This is just China culture. If there were 1b people in your country all fighting for limited resources, you'd be less apt to wait too. Most westerners (I am American) at first feel really mad at the Chinese for lack of manners (which to an extent it is), but when you realize that the situation and environment is different you begin to understand.

As for crotchless pants, that's just China. Kids learn to be potty trained faster in China. Just different.

Everything happens for a reason here in China.

Most of the time, convenience and selfishness are mostly the reasons.

True, but keep in mind it's a dog eat dog world, if there were this many people where we came from (US, Europe, Singapore) we'd start acting like that too.

I find myself acting very unAmerican in China. And when I come back to the US for visits, I do things I never would have done prior to coming to China.