You can try before you buy
While I'm in no way advocating for ice cream shop-level sampling, a quality beer bar will never shy away from offering its customers a little taste before they decide on a pint. Some places even offer flights for more indecisive clientele. In a marketplace as crowded as craft beer's has become, even the nerdiest of beer experts can get lost in the shuffle. There's no shame in asking for a sip -- the best beertenders always value education over expediency.
The bartenders know their stuff
The dudes manning the sticks should be adept at talking shop with any customer, from Stella-swigging newbies to over-saturated neckbeards and everyone in between. The last thing a great beer bar wants is to turn a potential craft convert off with false information or a poorly trained staff. So, if your bartender can't explain the difference between a porter and a pale, feel free to get the hell out of dodge.
Beer isn't paired with attitude
At the same time, nobody likes a wiseass. With all the different styles, brands, and unfamiliar terms, craft beer bars can be super-intimidating places for newcomers, and facing off with a snobby staff is just another barrier keeping drinkers from making the switch to craft. Even fancy-pants beer bars realize that beer should be approachable, interesting, and fun -- it's only beer, after all. Everybody should be able to get behind that.