Then, she was over at a friend's house this afternoon when Sam came home from school. He was happily showing off his many valentines from his friends and then confided that he had "sneakedd a cupcake into Grace's mailbox". He got a cupcake from a friend, and decided to give his best valentine loot to his sister as a surprise.
So, next time I hear dialog like this:
Sam: "I don't want to argue with you."
etc..., I will remember that they really do love each other. A lot.