He was all affability, waving good-bye to his previous visitors, wishing them a safe journey, and greeting us equally heartily—even me, shaking my hand as warmly as if I were a senator myself, rather than a slave who in other circumstances might have been howling from one of his crosses. Looking back on it, and trying to fix precisely what it was that made him so disconcerting, I think it was this: his indiscriminate and detached friendliness, which you knew would never waver or diminish even if he had just decided to have you killed.

Robert Harris, Imperium (2006)