+1 my favorite dive in SF is Toronado, which also happens to be the best beer bar in the city. Cash only, jukebox in the back that has mostly metal 
. Rosamunde’s spot has been taken over by a former employee there and is now Berliner Berliner, also serving sausages and the like.
Also, back when I used to commute downtown regularly, Glen Park Station in Glen Park was a regular stop on the way back home. Not much of a beer selection but the drinks are cheap. Sometimes they had free hot dogs in a crock pot in the back.
