I know you have them, so post up and share. Here's one of my favorites. I know there aren't very many women on here so feel free to jump in, guys!
I bought my first mountain bike in 1993 from a local shop, prior to moving to Denver for a year. I didn't know much about mountain bikes but thought I would be ok. The shop guy told me it was brand new (thats why it was in the back) and that it was a perfect fit. It was quite expensive but had a good frame and nice components so I bought it. I took it home, had problems getting it to shift and it was making an odd sound. Took it back and the guy says "thats because you can't really use all the gears, only some of them work" I explained that I wasn't trying for any extreme combinations, but that it was jumping in and out of gear. He took it to the back, tinkered with it for a while and pronounced it fixed. At home, it still didn't shift correctly and was still making the noise. I flipped it upside down to take a look for myself and discovered two things: there was red clay mud dried inside the seat. We don't have red clay in my area. I also found that the chain was not run through the derailleur correctly. The noise and shifting problems were caused by the chain dragging on the outside of the derailleur. I then took it to another shop where the guy there told me the bike was used, was a discontinued model from a couple of years earlier, and that there was extensive wear to the chain. I vowed never to return to the original shop and I didn't, for over 10 years. But that will be my next tale...

I've never had an experience that bad in a LBS, but I've been pointedly ignored because I'm an old fart. I guess they weren't bright enough to figure out that old farts have lots of free time and money on their hands. Needless to say, they saw the back of me.

Luckily, we have an outstanding recumbent shop here in Tucson. It's 45 minutes from where I live, but I'll drive right past the store 5 minutes from where I live to get there. It pays to treat your customers right.

I've been ignored once too often. The only LBS I'll go to is 400 miles away, needless to say I don't get in there very often, only 6-7 times a year but they remember my name whenever I do get there. I buy everything online and just install it myself.

Walt