Aha! I hear some exclaim so China is not that safe. But this is not that kind of post.
The biggest annoyance here is the hawker phenomenon. In the big cities or at any major tourist site there they are. In abundance. With many different hooks to try to catch you. In Tianamen Sqaure, the most notorious are the "art students". They just want to "practice" their English whilst explaining their artwork. They are very convincing, but their ultimate goal is to get you to buy something.
On the wall its the "guides". You don't ask for them but they accompany you regardless. Appearing sporadically are "water bearers" selling many things besides. When the guides part company they explain their situation- farmers with little or no income and its a long walk back etc, etc. If possible enjoy their company and make them work for their money. At the end of the day its only a couple of USD so its no big sacrifice.
Now the biggest danger here comes to those of you who decide to cycle. Caution: beware of the traffic. Its incredible! Seamless chaos or insanity can best describe it. Constant beeping, disobeying road signs, all in a days travel on the road here. Occasionally you may want to pass a bus or other vehicle bigger than you. The danger is not because of the size. Its because of what may hit you as you pass by said vehicle. Yes, chances are as you pass by a bus (or similarly larger vehicle) you may be hit by errant spittle. People evacuate excessive mucus via open vehicular windows on a most regular basis. Eeewwwww!