Today, I got a phone call from a customer who was responding to a voice message left to him by one of the other techs in the shop. The key word here is "other", meaning "not me". So anyway, the main problem here was that he wanted a pickup installed, but didn't provide the mounting screws, and we didn't have any that fit. I'll admit, it's a sucky situation, but it's one better discussed with the technician in question. Unfortunately, he won't be in until Sunday. Again, crappy situation, but sometimes in life, these things happen and if the technician isn't here, he isn't here! Now this customer understandably was a bit bummed and wanted to take his guitar back in the meantime. This happens often (like if we have to order a part and it may take some time to arrive), and here's where you should pay attention:
If the technician has already done some work on the instrument, this must be charged on the work order, and any parts used must also be charged. If I'm not the technician who is working on it, how am I supposed to know what's been done and what to charge? Case closed, wait for the technician to be in. We don't tag-team repairs.
The customer then said he was bummed because he didn't have his guitar, and that he felt like it was a bit of a hostage situation. Well ok, now we're getting a bit out of hand and passive-aggressive. Is it my fault that I'm not your technician? No. Do I regret answering the phone now? Yes. Do I wish you could take your guitar back and shove it somewhere not so pretty? Definitely. Also, you won't DIE if you don't have your guitar. You probably won't lose your job, either, and it wont break up your family. A guitar is a tool for leisure, like a video game or Sudoku book. If you go camping and can't play your Xbox, would you call THAT a hostage situation?
The point I'm trying to make is that although certain situations in life suck, they're not really a big deal compared to, like, losing your job or running over your girlfriend's cat. So when you call your guitar repair shop and they don't give you the exact answer you wanted, try to understand that there's always a reason. Our job is to serve YOU, so if there's some kind of hitch, it's not to our advantage and we'd really also prefer to have everything go smoothly and for you to be happy. We're not the enemy, so please don't try the passive-aggressive card on us; it's not helping anything.
Addendum:

The Borg are a fictional race of aliens created by Gene Roddenberry in the Star Trek universe. What is unique about the Borg is that they do not possess a sense of individuality and are all mentally interconnected, like in a big network. All information possessed by the Borg is shared, all thoughts are shared, and they operate as one.
Store employees are NOT Borg, and if you ask to speak to, say, "Gus" and Gus isn't there, you cannot expect ME to have the same information as contained in Gus's head.
Ideal conversation:
You: Hi, is Gus there?
Me: No, sorry, he won't be in until Monday.
You: oh, ok, I'll call back then. Thanks!
Real conversation:
You: Hi, is Gus there?
Me: No, sorry, he won't be in until Monday.
You: ok well, I brought my guitar in and Gus was working on it and bla bla bla...
Me: WE ARE BORG. YOU WILL BE ASSIMILATED. RESISTANCE IS FUTILE.