"So there you go. Just like you can't have good without evil, you can't have happiness without sadness. And the sadness doesn't make the happiness less happy, right?"

Zetta was, after all, an idiot... but he did have a few notions about the fundamental workings of the universe. Being born to a species that exemplified evil, with a direct counterpart that exemplified good, meant picking up on an occasional subtlety like this.