There was only one thing about his own appearance which really pleased Hercule Poirot, and that was the profusion of his moustaches, and the way they… - Agatha Christie

Ah, but life is like that! It does not permit you to arrange and order it as you will. It will not permit you to escape emotion, to live by the intellect and by reason! You cannot say, 'I will feel so much and no more.' Life, Mr. Welman, whatever else it is, is not reasonable. [Hercule Poirot]

Never do anything yourself that others can do for you.

I suggest to you that, although you may have endeavored to gloss over the fact to yourself, you did deliberately set about taking your husband from your friend. I suggest that you felt strongly attracted to him at once. But I suggest that there was a moment when you hesitated, when you realized that there was a choice–that you could refrain or go on. I suggest that the initiative rested with you–not with Monsieur Doyle. … You had everything, Madame, that life can offer. Your friend’s life was bound up in one person. You knew that, but, though you hesitated, you did not hold your hand. You stretched it out and, like the rich man in the Bible, you took the poor man’s one ewe lamb.