Useful, little known facts about the world, though perhaps fictional:

"Dogs see ghosts. They see disease floating down the street like fog. They hear and smell the unimaginable. Yet dogs are indifferent to such things because they are simply part of their perceived world. . . .

Life and death do not mix. They could never dance together because both of them would insist on leading."

from "the Ghost In Love," which later explains why, for the dog in question, the absolute worst thing he can encounter is to hear harmonica playing, particularly if it is the recording of the harmonica part of Neil Young's "Heart of Gold."