At some point in the long, sleepy history of the cosmos, a pile of carbon atoms looked around and said, "Wait... what is all this?"
That moment - whenever and wherever it happened - was the beginning of consciousness, the universe's most audacious experiment in self-awareness. Before that, everything was just physics behaving itself. Then, suddenly, there was curiosity. Stars burned, planets cooled, and on one of them, matter developed opinions.
That's consciousness in a nutshell: the universe talking to itself and occasionally forgetting what it was saying.