Zeitgeist is the best Dive Bar with a huge outdoor patio filled with picnic tables. Great music, good beer selection, great Bloody Mary's, generous portions of grilled meat and the carefree attitude of almost everyone there makes it a popular standby. It is so cool that you can drink outside in the garden, this place has tons of character. Located in the Mission Neighborhood.
199 Valencia St.(at Duboce Ave)

I'll second the recommendation for Zeitgeist. Definitely a place where lots of hipsters flock, though. So you might not want to go with your cardigan wrapped around your shoulders And they have awesome burgers....mmmm...burgers....