Curious things, habits. People themselves never knew they had them. [Witness for the Prosecution, also published in The Hound of Death and Other Stories.]

There is something about conscious tact that is very irritating.

Evil never goes unpunished, Monsieur. But the punishment is sometimes secret.

Tea! Bless ordinary everyday afternoon tea!

Hate doesn't last. Love does.

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.

To every problem, there is a most simple solution.