The definition of secret is something that is kept or meant to be kept unknown or unseen by others. If you are told a secret it means you can’t tell anyone. Except you always tell your best friend. It doesn’t matter if it’s a small secret or a life changing, totally mind blowing, important secret. If you don’t tell your best friend, chances are you're not actually best friends. The problem is, if you tell them, it isn’t really a secret anymore. More like a concealed fact that only you two (and the secret teller) know. Of course, you could choose not to tell your best friend, but then what would you do? You can’t keep a secret to yourself, it’s not human nature. So, obviously, they should update the definition of secret.