Check out my post about why sisters are special:http://mysisterismybestfriend.blogspot.com/2012/06/sisters-are-spec...
Loved your post! I have sisters, too, and I believe it's the closest you can get to cloning yourself. No matter how many fights or how angry you get with each other (as we do with ourselves), when you hurt, they hurt. When no one else knows what to do, your sister will think about how bored you get with the cafeteria food at the hospital -- a small thing that shows an infinite amount of compassion, consideration and empathy. Great post.