J.J. Rousseau said that the first man that fenced a piece of land and called it his own is the biggest enemy of humankind. But, in my opinion, the bigger one is Philo T. Farnsworth, the man that invented TV.
What if… we are robots invented by earlier Earth masters who rebelled and destroyed their creators (e.g., Atlantis)? Or they had a fatal design flaw in being able to reproduce? This is just a hypothesis, of course…