Crime is terribly revealing. Try and vary your methods as you will, your tastes, your habits, your attitude of mind, and your soul is revealed by your actions.

How often have I not heard a perfectly intelligent female says, in the tone of one clinching an argument, 'Edgar says -- ' And all the time you are perfectly aware that Edgar is a perfect fool.

One must make one's own mistakes

Coffee in England always tastes like a chemistry experiment.

Men don't understand how their mannerisms can get on women's nerves so that you feel you just have to snap.

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

I suppose it is because nearly all children go to school nowadays and have things arranged for them that they seem so forlornly unable to produce their own ideas.