Ask HN: San Francisco's Best Coffeeshops for Writing Code

I was always skeptical about writing code at coffee shops, but have just tried once and found out that I was way more focused and spent time much more effective than from home. So I want to explore it a bit more and was curious what is the other peoples' experience.

So a question for those who don't work at offices. What are your favorite places in San Francisco to write code/make a design? Places where you would go instead of working from home. And do you find working from coffeshops more effective than from home or just go there to feel more social?