I have driven in San Francisco. As a rural Midwesterner accustomed to people leaving space between cars and slowing to allow people to merge onto the freeway, SF drivers are among the rudest I've had the misfortune to mingle with, and I've driven everywhere from my home in Michigan to Canada, the East coast, the deep South, the mountain states (one of the nicest places to drive, in my experience), Canada, Mexico, China, and California. Only in the outskirts of Shanghai have I experienced drivers that were less cautious and less respectful of my car's right to the road than those in San Francisco.
Fortunately, when I was in San Francisco, I was on vacation and therefore content to simply get to my destination a little later, taking back roads and continuously rebuilding the space in front of me, avoiding rush hour like the plague - but wow, those automated cars are getting a stress test. I just hope they're not programmed to drive like the Californians building them!