I can't say I've had any horrible experiences, but I have had a few mildly irritating ones.

I went into a branch of a small chain bike shop a couple of months ago looking for tubular glue and neither of the employees had ever heard of tubulars or any type of tire you glued on to a rim. They did know about tubeless though, and thought I was trying to glue the beads on a tubeless system, which didn't strike them as surprising.

I pre-paid for a cycling jersey and bibs at another LBS on February 17 and still haven't seen them. They've been holding $230 of my money for almost two months now. I'm in no fear that the shop's going to stiff me, but it seems like a long time to wait even for a special order.