The main character of "The Tell-Tale Heart" promises us a tale of cunning and cleverness, and delivers. At the onset, we doubt the cleverness; maybe we even feel cleverer than the story. But as Edgar Allan Poe's ten-paragraph masterpiece unfolds, we find we are caught in the story's web, just as the characters are. We must regain our cunning and cleverness to get out. It'll make us smarter.
The narrator's cunning is nullified by his cruelty.