Not really a horror story, but still one of my fav music store stories that brings a chuckle anytime I recall it.
Church guys were always the worst on trying to beat you up on prices. I was working a deal on 5 wireless Shure handhelds with a pastor and his music minister. They were haggling like there was no tomorrow. They had already taken up almost an hour of my time demoing the mics and being fairly obnoxious with their attitudes. Such is sales though, you learn to deal with it.
I had already matched the lowest internet price we could find, and they didn't have to pay tax because of their church affiliation. But they still wanted more, "throw in some speaker cables and mic cables for free". I had just quit smoking the day before and was "feeling the burn". I told them I was sorry, but I couldn't give them free cables, but would match the lowest price we could find online.
When I went to search the net for cables, I had a brain fart and couldn't recall the brand to save my life. I apologized and told them I was a bit scrambled because of having just quit smoking. They immediately went into, "turn that over to God son, he'll take that burden off your back" "smokings a sin and you can be healed of it if you give your life to God"

Not exactly what I was in the mood to hear at that moment. Good intentioned or not, I was craving that nic pretty badly.
My manager, who was sitting close by and playing guitar while listening, had had enough of them. He smiled and asked the two of them, "Have you turned your overeating problem over to the Lord?" Both of them were on the heavy side.
Needless to say,...I didn't get the sale.