Charles C.
Yelp
It's the best bar in America, by virtue of subtraction. Let me explain.
1. It's not a performance space. There's no room for it, so unless you're running the music round at Tuesday Trivia (at 9pm), take your guitar elsewhere.
2. It's not a dance hall. Again, there's no room for it. While there's a jukebox, it isn't meant to be your DJ. The disco ball is only utilized once a year.
3. It isn't known to be a great restaurant, though the food is pretty decent. Nothing to write home about, but if you need a bite (until 10pm), their fare will more than suffice.
4. It's not a sports bar. There are three tv sets whose content is skewed towards bay area teams. If you want to catch your favorite out-of-market team this isn't the place to do it.
5. It's not a place to "be seen." Sure, you might run into some attractive patrons, but nobody gets dolled up to go to the Bitter. You'll find people from the neighborhood and a lot of locals, dressed, well, normally. Miniskirts and stripey shirts are rare, though feel free.
Think about why you go to a bar in the first place, then cut the crap. What are you left with?
A comfortable place to talk, and booze.
The Bitter provides both of these well, and nothing else.