although we have a local sam ash, i have had no dealings with them, even though we have been in several times.
have much experience with GC, and like the last poster, have had no trouble returning things.
we have a good relationship with several of the people there, and i would say the answer to your question is an unqualified YES...you can develop relationships, and i urge you to do so.
very helpful (in fact, GC employees hooked my son up with his present band)
go in regularly, meet with your regular guy, and you will be surprised how nice and helpful they can be