Do you not realize, Hastings, that each and everyone of us is a complete mystery with layers. We each try to judge each other, but nine times out of … - Agatha Christie

That’s the depressing part of places like this. Guest houses run by broken-down gentlepeople. They’re full of failures — of people who have never got anywhere and never will get anywhere, of people who — who have been defeated and broken by life, of people who are old and tired and finished.

If one man does not make a move, the other must, and by permitting the adversary to make the attack one learns something about him.

"And yet," said Poirot, "suppose an accident-"
"Ah, no, my friend-"
"From your point of view it would be regrettable, I agree. But nevertheless let us just for one moment suppose it. Then, perhaps, all these here are linked together - by death."