Cutting in line is common. It seems to annoy locals, but also seems like it's kind of light-hearted game for everyone. Grandmas get carte blanche to cut as they please, and if you get in their way they will hit you, but it's a grandma so it doesn't hurt and is quite funny the first time it happens.
Jay walking is rampant except at intersections that are staffed with numerous traffic police.
If you're fat, people will comment on your fatness while getting to know you for the first time. This is not meant to be offensive. Likewise if you're skinny, bald, old, etc.
There is an odd mix of authoritarian rule obsessed workers and then many who break the rules any chance they get.
They are extremely friendly and interested in a lot of foreigners. Chinese strangers would buy me food and translate for me without me even asking.