" Sleep was a vehicle for passing the time, for avoiding the present. It was a trolley for the depressed, the impatient, and the dying. Donald was all three. He turned out the light beside his cot and lay in the darkness. The cryopods and shifts were exaggerated forms of sleep, he thought. What seemed unnatural was more a matter of degree than of kind. Cave bears hibernated for a season. Humans hibernated each night. Daytime was a shift, each one endured like a quantum of life, all the short-term planning leading up to another bout of darkness, little thought given to stringing those days into something useful, some chain of valuable pearls. Just another day to survive. He "

― Hugh Howey , Dust (Silo, #3)