basically, everyone is different in personality,but I suppose Japanese pay more attention on politeness and more serious on work, Chinese are just easygoing both of them

Well, I think it is very hard to give you a general answer about the differences. Different people possess different personalities, and that is quite ture even though they are from the same country. Besides, in my opinion, strangers turn to hide some of their personalities and exaggerate the others, so that every one looks kind and polite. If you really want to investigate more of it, I just suggest you asking this question on an international forum. I'm not saying that italki is not international enough, but you just need one where many overseas live in one country for long, so that they have experienced the culture collision in their daily life there, and they do know the basic and even root cause of the personality differences.