Answer:
Pride.
Step-by-step explanation:
Edgar Allan Poe's short story "The Cask of Amontillado," tells the story of how Montresor took his revenge upon his friend Fortunato for all the "insults" that he's had received from the latter. The deception with which Montresor lured his victim was based on pride and ego, leading to the unassuming Fortunato to be buried alive.
One main reason for the whole revenge plot is to pay back Fortunato for "the thousand injuries" he had tolerated from him. And even for Fortunato, his pride in his knowledge of good wines led him to be taken into the catacombs without a doubt. Had he merely accepted that he may not be the best judge of wines, he wouldn't have died. But as he persisted on going to taste it, despite the "cold" that he's suffering from, all comes together leading to his ultimate death.