Here is the thing: you can’t be intimate with everyone. All societies depend on a certain degree of formalism, and rules of behavior and etiquette. This holds particularly true in diverse societies.
BUT, I think many people are not truly intimate with ANYONE. They have friends, yes, but superficiality can be a self reinforcing circle. Connecting at a surface level leads to shame, and that shame causes you to feel the need to “apologize” to stay in the group, and this happens with everyone. Pretty soon you have a stereotypical fraternity or sorority social milieu, where everyone pretends to be happy, but they stay drunk most of the time.
I think the problem is that Americans grow up with continual noise and banter. TV’s are everywhere, and radios, and smart phones, and you know the drill. Kids are socialized like that. They are socialized by devices perhaps as much or more as by people.
For any level of emotional depth to develop, you need time and silence. If you busy all the time and surrounded by continual noise, then you will be a superficial person. I think this is true, or largely true.