The most noticeable things when you go to China

First, there are so many public security officers, and they patrol on foot very frequently. In first-tier cities, there is hardly any place where you won't see them.
Second, there are tons of outdoor street tables, and many people come out to eat late-night snacks.
Third, there is a strong club and pub culture. A unique point is that the atmosphere allows older people to hang out together; while people tend to stick to their own circles, you rarely get turned away from an entrance just because of your age.
Fourth, there are many live bars. You'll see many unknown singers performing.
It feels a bit like Korean culture from the early 2000s. Shanghai and Beijing feel like Korea does these days, so I recommend Chengdu, Chongqing, Wuhan, or Guangzhou.