i've had most of that stuff in the original post happen to me (not all in the one shop)- i always bring my own picks, though, as i like a weird gauge, really thick.
for me, a shop is good if it:
- lets me try what i want (within reason- if they have a genuine 1959 LP standard, for example, i wouldn't even ask to try that)
- leaves me alone when i'm trying gear, after i've been set up with the right kit (leads etc.)
- lets me turn up (or better yet, has a soundproof try-out room)
- doesn't pester me with sales pitches or asking me constantly if i'm going to buy, and allows me to try stuff for a decent amount of time
- has a decent selection. I realise they can't stock everything, but some nice stuff would be nice.
- actually listens to me if i do ask for advice
- doesn't treat me as an idiot just because i "don't work in a music shop"
- doesn't try to second-guess what i want to try. Newsflash- i already have most of what i need for the main types of music i play, i don't need to be told that a tele doesn't work for 80s shred, because maybe i just want a tele.
- not act like i'm wasting their time if i want to try several different models- maybe i haven't decided what i want yet, or want to try several examples of the same model to pick the best one, etc.
EDIT: the thing which i really don't understand is, that if you really want to try it and they make you jump through a lot of hoops, you can just lie. :?
that being said, there are a couple of really nice music shops here which pass all, or most, of those tests- but several not so good, too. Once a shop here told me, in all seriousness, that marshall tube amps were the only tube amps you could get any distortion out of. o_O