One just round the corner from work failed to sell me the right length spoke despite him measuring the wheel with a ruler.
Not overly enamoured with any of my local shops. Got bike back from one after they'd replaced BB bearings and given gears a twiddle with a bent mech hanger which implied they'd never even given it a run to check.
Customer service at another is a fine blend of ignorance and arrogance.
In fairness I'm not a frequent flyer with any of them as I do my own fettling and generally buy online though as DT78 said customer service can swing it. When I lived in Bath, I'd buy from John's Bikes and pony up the extra cash purely on the basis of great service