The human mind is so complex and things are so tangled up with each other that, to explain a blade of grass, one would have to make a diagram of the universe.
Positive emotions broaden our awareness and encourage novel, varied, and exploratory thoughts and actions. Over time, this broadened behavioral repertoire builds skills and resources.
The writer must believe that what he is doing is the most important thing in the world. And he must hold to this illusion even when he knows it is not true.