"Everyone has his sharp-toothed sleep-destroying devil inside him, and this is neither good nor bad, but is life . . . This devil is the material (and basically what wonderful material) that you have been endowed with and with which you are supposed to make something."
-- Franz Kafka
(Note: Kafka wrote this in a letter to a very young woman he'd met at the sanitorium. He might not have been so upbeat in his own diary.)