"A fog can drift in from outside and get you; it can invade. At the long high window of his library--an Ozymandiasian structure built from concrete chunks that had once in another age formed an entrance ramp to the Bayshore Freeway--Joseph Adams pondered, watched the fog, that of the Pacific. And because this was evening and the world was darkening, this fog scared him as much as that other fog, the one inside which did not invade but stretched and stirred and filled the empty portions of the body.
Usually the latter fog is called loneliness"

Philip K. Dick
"The Penultimate Truth"