This was genius at close quarters, and genius had that something above normal in it that was a great strain upon the ordinary mind and feeling. All five were different from each other, yet each had that curious quality of burning intensity, the single-mindedness of purpose that made such a terrifying impression. She did not know whether it were a quality of brain or rather a quality of outlook, of intensity. But each of them, she thought, was in his or her way a passionate idealist.

Agatha Christie