The Taproom Experience

A great tap room, has clean taps and a diverse selection of beers. Sadly most tap rooms in the bay area california are dominated by strong hoppy beers.

I'd rather have larger variety of different beers than one or two different beers.

 

As many have said already, good beer, and a good variety of styles/abvs is the main key. After that the space is important, and I like a place that has a mix of beer hall, quiet pub, and sports bar, so you can have a nice quiet conversation, a loud rousing time with friends, or the enjoyment of just having a beer and watching the game.
I also think a cool outdoor space is key (weather permitting) as there is nothing like having a beer outside on a beautiful day.
I've seen plenty of examples of all of these, but my favorites so far have been Alesmith in San Diego, Stone in Escondido, and Boulevard in KC. Plus, just because it's a really neat place in my college town, Tallgrass Tap House is a place to check out if you are ever in Manhattan KS.

 

All I can say for sure is there should definitely be pizza available.

 

https://www.facebook.com/DorchesterBrewingCompany/posts/1598932993469131:0

Apparently everyone else likes making an already loud bar even louder.

 

I'm with @LeRose with cleanliness. There is a place in Denver that is the antithesis of what I like in a taproom. The place is grungy, everything seems to need a good scrubbing. All the books and games are hand me downs that are missing pages or parts. They don't use proper glassware, most of their glasses are goodwill "antiques" which is supposed to be part of their charm. Add in that they have a super Nintendo set up smack dab in the middle of the place and it all adds up to an experience that I don't enjoy. I really dig TRVE brewing, its clean, plays great music, and has a vibe that I dig. While its a metal place, it feels more sophisticated, like upscale gothic if that makes sense. And the beer rules.