Question

Why does Montresor, the narrator, want revenge?

Answer 1

There is no specific reason given for Montresor's actions. He spells out his personal justification in the famous first line of the story:

The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge.

Since both Montresor and Fortunato are wealthy members of the upper-class, it can be inferred that they strive for the same status and recognition in society. Perhaps Fortunato blocked Montresor from an honor, or took his place in some fashion; it is seen later that Fortunato is a member of the Masons and Montresor is not, which could show how Fortunato is seen by the public in a higher status. The insult, which pushed Montresor over the edge, could have been aimed at himself, or at a member of his family. Montresor here seeks to repudiate Fortunato, but in his own way, secretly, so only Fortunato knows how and why he was killed.