" The hallmark feature of intimacy is mutual responsiveness, that reassuring sense that you and your soul mate — or you and your best friend — really ‘get’ each other. This means that you come to your interactions with a well-developed understanding of each other’s inner workings, and you use that privileged knowledge thoughtfully, for each other’s benefit. Intimacy is that safe and comforting feeling you get when you can bask in the knowledge that this other person truly understands and appreciates you. You can relax in this person’s presence and let your guard down. Your mutual sense of trust, perhaps reinforced by your commitments of loyalty to each other, allows each of you to be more open with each other than either of you would be elsewhere. "

― Barbara L. Fredrickson , Love 2.0: How Our Supreme Emotion Affects Everything We Feel, Think, Do, and Become