I love hearing all your stories. Sometimes, I feel like it's just me who stores hate.
I shop embarassingly a lot and, in my experience, it doesn't matter what I wear. It's the person behind the "SA." If he/she is a cool person, he/she will most likely be a cool SA. I do prefer the smaller boutiques, though. Here in L.A., I get the best service at Patty Faye, Una Mae, X-girl, the Circle and the Kids are Alright. Note that all these stores are on the eastside. As you get more west, the SAs cop more of an attitude.
BUT the worst service I've ever gotten was in the most unexpected of all places: the Giant Robot Store (o.g. & 2) on Sawtelle. Their magazine is so laid back and funny and irreverent. For those of you who aren't familiar with GR, they're all about Asian pop culture. In addition to a great magazine, they sell cute t-shirts, accessories, books, toys, etc... Total geek boy/girl heaven! I've gone into their stores 3 times and every time I feel like I'm not hip enough for them. One time, I was PAYING for a pretty big purchase & I asked about a shirt in a different size. The guy said they had a bunch still in boxes that he was about to open. I said, okay, when should I come back? And the ***hat looked at me like I was his mom making him clean his room and said, "I don't know! It's really busy right now." I see his stupid mug on their website all the time and it makes me want to puke. The second time: I smiled at the girl as I was entering and she ignored me and went on talking to her friend. I see her picture all the time, too. f*ck you, b*tch. The 3rd and final time: I felt attitude as I was entering and I just turned right around & left. I'm never going back there again and it's a shame because I love their stuff and I'm in the neighborhood all the time.
End rant.
So, anyway, back on topic - it ain't just the luxury stores that have attitude. The Barney's on Wilshire is always a pretty cool place, though. And I'm not a very posh-looking person.