Why would you ever turn down the opportunity to get to know new people? If you don't like them that is one thing.  But if you don't get to know them for fear that you might not like them, that is not right.

Get out there, meet people, make friends, have fun.  The expat lifestyle is very transient.  We make friends fast and we lose friends fast.  It is just the nature of people always on the move.

It is like everything, you will meet those with whom you will "click" and those with whom you wont. They can be fun, informative, annoying, exasperating, sympathetic (especially after a bad China day).  I would encourage you to go out and meet them. If you get along, GREAT! If not, well, then you treat them with the same "social graces" as we do back West.

Why wouldn't you treat people, both locals and foreigners, the same as you would at home? I know some of you say, "When in Rome..." but aren't you... better than that? Set an example, not only for the locals, but for other foreigners. Having a temporary friend is better than having no friends at all, no? 

Friendships are different in China.  At home, I have options and can choose people who I have a lot in common with.  In China, options are limited.  There's language difficulties, smaller windows of opportunity due to people coming and going.

I understand not being able to stand some people (I've met some unbearable expats too), but most I can enjoy sharing a drink with.  It sounds like the biggest qualm you have with the others is the short period of time to learn about them, but that time is a luxury.  If you don't like them later, at least you'll know why you don't like them.

You're in a foreign country, options are limited. It's obviously different from being around people you've known for years but the thing is if you came here alone your only option IS to form friendships or make acquaintances with people in a short period of time, or else spend a lot of time lonely. You don't have to be best friends with people but why not give it a try? You already know you have something in common: you were crazy enough to move to China. Who knows, you might even like the person !

I think it is normal to have a frantic period of getting to know people when you move to a new place. My first couple of weeks here reminded me of freshers' week at university (yes, I can remember that far back!) When everything is unfamiliar it is nice to be able to chat to people in the same situation and who speak the same language. Not everyone you meet will become your friend for life, but how will you know if you don't give them a chance? What have you got to lose?

You should consider yourself lucky you are around other expats everyday and at have the option of going out with them or being friends with them.
Because of my job and the town I live, there are pretty much zero expats here, so I have made many Chinese friends instead.
Once a month or so when I need a fix I will head down to the city to an xpat bar to drink, and I always meet new people from all over the globe, but I have never become friends with any of them.
The previous answers I completely agree with.  Why would you not at least get to know them and decide after?

they're mining; stay away