Here are some things you should NOT do in China. I'll add a quick summary.
Shadeed Abdulmateen, an American citizen, was sentenced to death in China (for killing his girlfriend when she tried to break up with him).
Drug offenses are a big NO! Don't mess with drugs. China does not tolerate the threat of drugs. The penalties are severe, and there is simply no way around it.
There are many recent examples where expatriates have been receiving the death penalty.
Don't cause trouble with the locals. Don't attack women. The security system is very comprehensive. CCTV cameras are installed in all shops, restaurants, bars, pubs... troublemakers will be caught.
Harbin in winter.
Don't get involved in politics. For example, Taiwan is a sensitive issue. You can't just say whatever you want. If you're an American expat, you might be asked directly for your opinion on Taiwan.
Locals, especially in Shanghai, prefer to talk about business rather than politics.
The Chinese are patriotic. You are expected to show respect for the local culture.
Do not attempt to enter China illegally. First, it is not easy to enter illegally, and even if you manage to do so, you will be caught. Furthermore, do not overstay your visa. Penalties include a fine of 500 Chinese yuan per day, with a possible ban on re-entering China in the near future.
Terracotta Warriors of Xi'an.
Don't expect to find spoons and forks in restaurants. You have to get used to using chopsticks. It's so important...
Stop comparing China to this country and that one. China has its own unique charm. The more time you spend exploring China, the more you'll discover.