The best valentines have four paws and a tail--you don't need a professional pet sitter to teach you that. If you're a pet owner, then you already have a valentine, whether or not you have a human sweetheart. It's so easy and natural to love your pet that you probably don't need to stop and think of exactly why your cat, dog, or other furry friend is so precious to you. And of course, whatever your reasons are to love your pet, they are good reasons! But just why are...