Somewhere in the vast universe, there was a planet just like Earth. The only difference was that the people had tails on this planet, and their social rank was determined by the size of their tails. One day, a man arrived on the planet in a rocket from the Earth. When the man told the people of Bis Bis Bis Planet that only animals had tails on his planet, they hid their tails in great haste so as not to be considered creatures of low rank.
The size of one's tail decides one's social rank. Tezuka Osamu created such a world and told us how silly it is to behave motivated by vanity. It is best to stay just the way you are whatever the circumstances. This is his message, like the one in the famous children's story "The Naked King".