If you're ever in San Francisco try Pearl's Deluxe Burgers. They have amazing burgers and shakes. I had a peanut butter shake. Had small little shavings of peanuts and stuff in there. It sounds weird but was so good.
Then I came back the next day to have an Oreo mint shake. My friend had a chocolate banana shake. Had chunks of banana in it.
I had been there for burgers but this was my first time trying the shakes. A must try if you're in the city. Amazing.