You can observe a bunch of people and say, "they are not talking to each other because they are strangers". But if you observed a randomly selected group over a

You can observe a bunch of people and say, "they are not talking to each other because they are strangers". But if you observed a randomly selected group over a decade, you would see that some of them talk to strangers now and then, and those are the ones that have a tremendous advantage in creating new relationships, whereas the ones that never talk to strangers might even be handicapped/pathological. Like, there's a huge difference between someone who, on average, consistently starts a conversation with 1 of 1000 people they meet vs. someone who does that with nobody. But observing people for a minute or two at a time, you wouldn't see the difference.