Honestly, I've never had any complaints with the service at any of the chain bookstores I've been to. Most of the employees at places like B & N and Borders are relatively self-aware w/r/t their position in the world. They work in retail and they know that. Independently owned stores, be it book, record, or video, tend to be home to the real douches. Any of you guys ever been to Kim's Underground in NYC? Great store, but engage any of the employees in whatever fashion and they look at you as if you farted.
I do recall encountering an instance of snobbery at Borders, or at least witnessing it. I was at a store in Orlando where, in the DVD section, a display was set up called "_______'s Overrated Movie Club." This was several years back, so it had titles like Saving Private Ryan and Titanic. What was the point of that display? The guy worked in retail; it wasn't his place to put people down about their taste. (An aside: I'm surprised whatever supervisor/manager approved such a snide and flippant display. That would never have flown at the store where I worked.)