It could have been the enthusiastic look on Mitya’s face, or perhaps “that useless spendthrift’s” notion that he, Samsonov, could be taken in by such idiotic ravings as Mitya’s “plan,” or he may even have felt jealous over Grushenka, in whose name this “good-for-nothing” had come to him with a cock and bull story about needing money—it’s hard to say exactly what made Samsonov do it, but at the moment that Mitya’s legs had given way under him in despair and he had explained that he was lost, the old man had glanced at him with immense hatred and had decided to play a cruel trick on him.