I would say, yeah people in SF can come across a bit cold, but so do people in most larger cities, especially now during COVID. I now go out of my way to avoid people in a way I never would have before. SF pales in comparison to the overall apathy of places like NYC or London though. I find the weird outgoingness to strangers off-putting (as a Brit) in the smaller towns and cities in the states. People are always asking invasive questions, and it can start to get grating after the first few dozen times.