*sigh* I hate that sort of Homebrew shop employee. They really do a great job of ruining the hobby for so many people.
It's almost always the guy who's the "frustrated expert" type. Smart, but underachieving. For those hours they're at the shop though they can sound and feel like they're in the Royal Society and the customer a mere dumb petitioner. Even worse is the sort of aggressively volunteered "you're stupid" sort of advice that occurs with a regular basis.
The local shop employees can be a force for education and delight or a force for horrific soul crushing. The trick is to find the former and not the latter.
I was thinking of the immortal words of Socrates, who said "... I drank what?"