Unless the person in front of you is naked or wearing a particularly outrageous outfit, you look at the face first. In this respect, the smile says it all. Not all animals can smile, but humans do it beautifully. Without a single accompanying word a smile can say: ‘Welcome, come on in,” “Keep going, you’re doing OK,” or, probably the most valuable of all, “This is fun. I’m enjoying this and enjoying doing this with you.”