I'm not sure if this is appropriate to Aviation.SE, so apologies in advance if not.
I have taken several domestic flights over mainland China (as in, the People's Republic thereof) and, so far, it has always been a bumpy ride. I'm more familiar with flying (as a passenger on a commercial airline) around Europe and, to a lesser extent, the US and don't recall it ever being that bad. Likewise, the trip from Europe to China is reasonably stable.
Is there something about the weather or the terrain in that part of the world that causes this? (This, anecdotally, appears to apply both to flights across China, over the mountainous regions, as well as along the relatively flat eastern seaboard.) Or have I just been unlucky?