It's not necessarily a GC only thing- the kind of "I'm not in retail, I'm a Music Industry Insider" mentality that I've come across in salespeople, Here in New England there's Daddy's Junky Music- and for a while it was unbearable to even get some guitar strings at the local store.
The counter was on a
pedestal, so the customer was 2 feet below eye level, and the snottiness was rampant. I heard customers sworn at, belittled, and was on the receiving end of poor anger management twice myself. I gave up for a couple of years (this after ringing up heavy receipts), until they changed locations, managers, and at least one of the heavier-attitudinal clerks (the one with the choicest list of stupid quotes, not ironically).
Recently it has been a great place to find obscure stuff, and the new and remaining staff are good guys who know enough, and don't pretend to know what they don't know. In general I like to do business there because it is a more or less local thing, vs. the GC onslaught- I try to fund that as little as possible.
