... nothing is so boring as devotion.

Does the real thing ever have the perfection of a stage performance?

Difficulties are made to be overcome ~ Miss Felicity Lemon, Agatha Christie's Poirot: The Plymouth Express

Then there are some minor points that strike me as suggestive - for instance, the position of Mrs. Hubbard's sponge bag, the name of Mrs. Armstrong's mother, the detective methods of Mr. Hardman, the suggestion of Mr. MacQueen that Ratchett himself destroyed the charred note we found, Princess Dragomiroff's Christian name, and a grease spot on a Hungarian passport.

An appreciative listener is always stimulating.

A mother's love for her child is like nothing else in the world. It knows no law, no pity, it dares all things and crushes down remorselessly all that stands in its path.

Unless you are good at guessing, it is not much use being a detective.