The clues in this case could lead to a few different conclusions so it was actually a good one for trying to guess the ending. Sometimes in Poirot stories I feel like his conclusions just come out of nowhere. Yet while this was one of the best Poirot mysteries, Christie uses her fictional author, Ariadne Oliver, to deliver lines that are obviously Christie's feelings about her own detective.
"How do I know why I ever thought of the revolting man? I must have been mad. Why a Finn when I know nothing about Finland? ... Why all the idiotic mannerisms he's got? These things just happen. You try something--and people seem to like it--and then you go on--and before you know where you are, you've got someone like that maddening Sven Hjerson tied to you for life. And people even write and say how fond you must be of him. Fond of him? If I met that ... Finn in real life, I'd do a better murder than any I've ever invented."
Learning to pay attention to the details,
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