Is silence golden?

What is it about speaking that makes us think it is necessary? We refer to silences in conversation as awkward. If no one speaks at the dinner table for more than a couple seconds, someone cracks a joke to break the quiet. It seems logical that it would cause more discomfort to sit in silence with a stranger than with a friend, but that is often not the case. It is more natural to sit wordless in a plane next to a complete stranger than to sit in silent thought next to a friend.