Once upon a time there were two cave men: Fred and Barney.
While Fred and Barney were out hunting one day, they found themselves treed by a sabre-tooth tiger.
When they returned home, one of the tribe members asked Fred where they had been. Fred said, "Uh, we got treed by a sabre-tooth tiger."
Another of the tribe asked Barney, and he told the story of how the sabre-tooth had chased them across the plains, towards the tree. Making wild gestures he showed how Fred's arms flailed as they ran.
Whenever he told the adventure the cavemen laughed hysterically. This was something new, something uniquely human. Laughter itself wasn't a new thing: hominids laughed, chimpanzees laugh, I've even seen a dog laugh, but until that day laughter had always been in response to an imediate event - you see someone slip in the mud and you laugh. But, now the cavemen were laughing at Barney's relating of an event - to the pictures imagined in their minds through his storytelling.
That night, they gathered around their latest discovery - fire, the element that separates man from beast. Without fire the nights are wasted, there is nothing to do but huddle together and fear predation, just like every other animal. But fire brings warmth and light, it makes the night a functional time for small projects, like tool making and art. With fire we get community, camaraderie and an easier to digest diet. But, most importantly, fire gives us the very thing that allows us to grow in ways bound only by our imaginations - it gives us leisure time.
And, around that fire, hundreds of thousands of years ago someone said, "Hey Barney, tell us about the time that you and Fred got treed by that sabre-tooth."
From that day forward people forgave Barney's poor hunting skills because he provided something their growing minds and culture desperately needed - entertainment.