It is mixed. Tomman says it is all friendly, but I think that it is not all friendly. Some of it is. But, actually, it seems that friendliness is the wrong way to measure this kind of thing. There are other things, like consideration, empathy (the golden rule), and sincerity that are often lacking among people who mean no harm. That might be what bothered your friend.
I also disagree with liumingke, I think foreigners adapt to it in waves-after some months it is not so bothersome, some months later it is bothersome again.
My own reply is that, generally speaking, most people in Kunming go too far with staring at "laowai". They stare too much. Most don't even smile when they do it, but the point is-that they wouldn't like to be stared at that way, and they should be able to predict that it is a problem that laowai faces everyday. But they either don't get this, or don't care.
About practicing English, it is often fine or harmless, but sometimes it feels cold to make "friends" with people who don't want to know you deeply. Basically, most people don't want to be close friends with a foreigner. At least not based on having something in common.
Most want to talk to them out of curiosity. Again, the golden rule. It would be good to stop and think if someone asked you the same things all the time, by people that you will never see again, would that bother you? Yes, it would.
Others want to practice their English, and that is fine if that's all it is and they say so. But, it is insulting when they say "I want to make a friend in order to practice my English". Others want to look cool, to gain face in their community by being seen with a laowai-it appears that they have connections overseas.
I have met some of the sweetest people in the world in Kunming, but lets not pretend that most of the current customs for interacting with foreigners are going to be considered inviting and warm, (unless one is simply a traveler on holiday, and therefore not looking for acceptance).