To the extent that many LBS's are privately owned, you'd expect a wide range of experiences shopping at them. Some will have a vibe you like, some won't. (The better ones will offer you beer!)
To me, it seems like in the ideal case you visit your own local enough the achieve known (and welcome) regular status - and this doesn't really mean buying a fancy bike. Visit often, spend some money, and try not to give the appearance that you're just trying stuff on to go home and order from Amazon.
I wouldn't be surprised if I knew more about a particular bike than the sales staff - particularly if I had been obsessing about and researching that very bike for days or longer (I only have 3-4 bikes to obsess over - how many bikes do they have on the floor?). And, while I might know what groupset the bike has by heart, that's probably not as useful information as what the guy that built that particular bike has. Anyone can memorize a parts sheet.
Of course; if you do all your own wrenching and own a truing stand just order your bike online because you don't need expert mechanics. Or do you?