Kisses have been scientifically proven to make owies better. I read that once somewhere, but always believed it even before science proved it. Just the act of someone wanting you to feel better?
Overhearing this the other day: a little girl bumped into rocks and scrapped up her leg. Her dad asks her if she wants him to kiss it better, this is what she tells him. "No, your kisses don't work. Only mommies do."