There’s a marked difference between what you can say to strangers and what you can say to your friends. In San Francisco, this difference is especially large. It’s simultaneously the city of independent thinkers and the city of political correctness.
I think this is because of the nature of tech startups. To found a disruptive startup, you need to see the world clearly, which usually involves having ideas that offend people. At the same time, in a seller’s market like software engineering, you need to please people for them to want to work for you. Because we mimic our successful neighbors, this culture spreads even to non-founders.
This makes it extra important in SF to have trusted friends, people with whom you can say what you really think. Without them, despite its homogeneity, the city feels lonely.