In my case I've tried different stores and so far had no luck. This one is the closest to my house and the one I've bought from the most (including several bags). It's not a big store so everyone knows everyone ... If I change SA again, I'm going to have to start over by finding yet another store - which makes it hard considering stores tend to be more receptive to those who come in person. Oh and this isn't my original SA, this SA inherited me when my ex-SA left.
I think it's really a matter of luck. You don't know whether your SA is good or not when you first start to deal with them. You won't even know until after a while and by then it's always awkward to change SA. Anyway, right now I'm just refraining from goign to the store, period. I am re-evaluating things and am calling overseas as well. If I can find a good SA overseas, then I'll stick with overseas as opposed to local, although that will be hard.
Another thing I found is that there are some SAs who are just rude but nothing is ever done about them (my SA is NOT rude, I'm talking about a different SA). Some of the rude SAs I've read about have apparently been working at the store for years. So if other ppl's complaining doesn't do anything, then most likely nothing will be done. It also means that perhaps some of the rude SAs may be important people at the store and that's why they are still there. Just a theory though ...