In my experience, married foreigners in China are the most smug and arrogant, although some are not. What causes this arrogance? It is hard to say.

Also, they tend to be some who do not know Chinese well at all. I met one british guy who was married to a younger chinese wife who was "smug", would not really say he was arrogant though. I also do not understand the root causes of it, most people back in their home countries will think they are marrying down, not up.