The popular idea that a child forgets easily is not an accurate one. Many people go right through life in the grip of an idea which has been impressed on them in very tender years.

You are the patient one, Mademoiselle,' said Poirot to Miss Debenham. She shrugged her shoulders slightly. 'What else can one do?' You are a philosopher, Mademoiselle.' That implies a detached attitude. I think my attitude is more selfish. I have learned to save myself useless emotion.

There was a moment when I changed from an amateur to a professional. I assumed the burden of a profession, which is to write even when you don't want to, don't much like what you're writing, and aren't writing particularly well

The young people think the old people are fools -- but the old people know the young people are fools.

Hasting - There are times when it is one's duty to assert oneself.

You have a tendency, Hastings, to prefer the least likely. That, no doubt, is from reading too many detective stories.

You don't realize what fine fighting material there is in age. ... You show me any one who's lived to over seventy and you show me a fighter - some one who's got the will to live.