Everypony has a secret, every single one. Even six normal ponies living in the average town of Ponyville. No matter how friendly a pony is on the outside, they have something on the inside that makes them special. The feelings of revenge, sudden regret, being useless, emotions boiling over, loneliness, and curiosity can really be a burden. Despite that the friends won't tell their own pals about it, they all can show empathy to one another; because they all have secrets themselves.