Radical Alterity

So one point in this book that struck me was when it was talking about intimacy between enemies and/or strangers. At first I did not understand it but then as it went into explanation it really began to make sense. If you know someone inside and out their is no need for conversation or communication between the two people, basically their is no intimacy. And if you dont know someone you have an intimacy to develop with that person, you have a basis for alot of communication between the two people. Maybe this is why their is the saying that opposites attract, you have more to offer one another. Yet, my question is what about two strangers that have the same morals and beliefs? Is their still intimacy between them? If everything is the same between the two and that is communicated is that where the intimacy stops? Are two strangers who have no simular beliefs, morals, and lifestyles more intimate? What defines intimacy?