I spent of couple of hours in the Mission District as a result of reading a small article in the local newspaper. The story was about a community group trying to restore and protect murals in the area.
The Mission (or at least the part I visited) is Hispanic and the themes expressed reflect that.
The Murals are everywhere, but I've concentrated on the ones in "Balmy Alley" which is a little lane between 24th and 25th (Harisson and Treat cross streets) as this was the focus of the article.
Mission is an area with a concentration of trippy dive bars and uber cool places of the moment. Guide books caution not to stray from the lights and crowds at night as the area, though being gentrified still has its dangerous elements. I never made it at night so can't report one way or the other.