"The Cask of Amontillado" builds towards a suspenseful conclusion by presenting, in a chronological way, the method that the narrator uses to get revenge on Fortunato. At the beginning of the story, the reader knows that the narrator, Montresor, seeks revenge, as he says of Fortunato, "when he ventured upon insult I vowed revenge." The reader also knows that Fortunato has what the narrator calls "a weak point"--his pride in his knowledge of wine. However, the reader does not know how Montresor will use Fortunato's weakness to get revenge. As Montresor leads Fortunato through the damp vaults and Fortunato begins to cough, Montresor attends to Fortunato with what appears to be kindness. The reader does not quite understand how Montresor will get revenge on Fortunato merely by bringing Fortunato to a vault, and Montresor is so seemingly kind to Fortunato that it seems uncertain that he will ultimately get revenge.
By taking the reader through each stage of Fortunato's descent through the vault, Poe builds suspense. There are clues that Montresor is bent on his friend's destruction, such as when he tells Fortunato that the Montresor family crest is one in which "the foot crushes a serpent rampant whose fangs are imbedded in the heel." This symbolizes Montresor's eventual murder of his friend. Montresor then takes Fortunato to part of the crypt where "the walls had been lined with human remains," another sign that death is coming before Montresor finally buries the drunken Fortunato in the crypt forever.
Unlike "The Cask of Amontillado," the suspense in "Sonny's Blues" is on a psychological level. The narrator wonders why his brother has been arrested for selling heroin. The story begins, "I read about it in the paper, in the subway, on my way to work. I read it, and I couldn't believe it, and I read it again." The story uses flashbacks to help the narrator--and the reader--understand how Sonny has gotten to this point.
The narrator begins to remember the past. He thinks:
"This was because I had begun, finally, to wonder about Sonny, about the life that Sonny lived inside. This life, whatever it was, had made him older and thinner and it had deepened the distant stillness in which he had always moved."
Sonny's deeper psychological motivations are a mystery to his brother until the narrator goes further and further back into time and into his family's history. The narrator realizes that Sonny and his father never got along; he says, "the principal reason that they never hit it off is that they were so much alike." The narrator also realizes that he has been dismissive towards his brother's dreams. When Sonny tells him that he wants to be a musician, the narrator thinks, "I simply couldn't see why on earth he'd want to spend his time hanging around nightclubs, clowning around on bandstands, while people pushed each other around a dance floor." It is only at the end of the story, as the narrator sees Sonny playing music, that the narrator understands his brother's struggles. This form of flashback narration works because the narrator needs to go back in time, to mine his brother's past, to understand what makes his brother tick and why his brother has suffered so much. Presenting the events of the story in a chronological way would not achieve the effect of going back in time to understand the present.