And what do you really do? asked Tiffany. The thin witch hesitatied for a moment, and then: We look to ... the edges, said Mistress Weatherwax. There's a lot of edges, more than people know. Between life and death, this world and the next, night and day, right and wrong ... an' they need watchin'. We watch 'em, we guard the sum of things. And we never ask for any reward. That's important.
Terry PratchettParticles of raw inspiration sleet through the universe all the time. Every once in a while one of them hits a receptive mind, which then invents DNA or the flute sonata form or a way of making light bulbs wear out in half the time. But most of them miss. Most people go through their lives without being hit by even one.
Terry Pratchett