It is my experience that no one, in the course of conversation, can fail to give themselves away sooner or later. Everyone has an irresistible urge to talk about themselves.

Who are you? You don't belong to the police?' 'I am better than the police,' said Poirot. He said it without conscious arrogance. It was, to him, a simple statement of fact.

Jealousy, you know, is usually not an affair of causes. It is much more-how shall I say?-fundamental than that. Based on the knowledge that one's love is not returned. And so one goes on waiting, watching, expecting...that the loved one will turn to someone else.

It's like all those quiet people, when they do lose their tempers they lose them with a vengeance.

One place is very like another.

The simplest explanation is always the most likely.

Evil is not something superhuman, it's something less than human.