This one pains me, because I worked as a shop rat through college and grad school, so I have some serious bike shop sympathy. But here's a scenario that's starting to wear on me now that I've taken off the apron for good and moved to the other side of the counter.
I need Part A. Nothing terribly exotic, just a standard widget to keep one of my semi-current steeds running. Maybe it's an 8-speed cassette. Maybe a 110mm bolt-circle-diameter chainring. Or maybe (and this is the one exotic on my list) it's a part or accessory not branded by Specialized, Trek, or one of the three dozen Trek subsidiaries.
So I go to Local Shop 1: "Do you have Part A?"
Response: "Uh, what's a Part A?"
Shop 2: "I'm looking for Part A."
Response: "We don't have it, but have you seen the new Madone?"
Shop 3: "I'll speak slowly: I... NEED... PART... A."
Response: "Dude, do they even MAKE those any more?"
Shop 4: "Oh for the LOVE of LANCE, tell me you have Part A!"
Response: "Uh, lemme look..." (five minutes elapse) "No, but we could probably order one."
It's reached the point where I follow the "four-call rule": Out of (semi-)respect for those who wrench, I'll call my four nearest shops. If anyone actually a) knows what I'm talking about, and b) has what I'm looking for in stock, they get my business. If I get four variations on the answers listed above, I go online and find it for myself.
I know, my karmic payback will come. There will be a day when I need a tube, and all the shops that could have sold me one will be boarded up. Of course, even if they had stayed open, the counter-guy would probably have said, "Whoa, tubes are so retro, dude. You totally gotta try these new Bontrager four-spoke tubeless carbon disc wheels!"