14. When She Cries, You Cry
When your best friend is upset, your first reaction is to punch whoever made her cry right in the face. Once she's eventually calmed down and explained that her family goldfish has died, you will sit and cry with her until she's ready to stop and eat some ice cream. Regardless of the situation, whenever she is upset, you're upset for her and vice versa. You're sisters; you feel each other's pain. On the other hand, of course, you also share every smile and laugh, and her happiness is the quickest way to improve your own mood.