Cask of Amontillado Response

Though I didn't enjoy it as much as Tell Tale Heart (which, thanks to its involvement in my childhood, I admittedly have a personal affection for), I definitely did find Poe's "Cask of Amontillado" to be an interesting short story.  Jumping straight to the ending to begin with (hooray dyslexia!), I was definitely confused by what ultimately had happened, and had to re-read the last few lines just to make sense of it.  At first, it seemed to me that Fortunato had somehow escaped his imprisonment and disappeared after he didn't respond to Montresor's "Indeed, for the Love of God" quip, and then evidenced nothing but a ring of the bells when Montresor looked in to check on him.  It of course instead turned out that Fortunato was silently protesting his own demise in an effort to not give Montresor the satisfaction of seeing him wail and plead anymore, but the way in which Poe ended this particular story of his just struck me immediately as not nearly as...concise as his other ones?  Deliberate?  Devoid of loose ends? I can't quite put my finger on it, but ultimately what I'm trying to say is that for all its darkness and bizarre makeup, "Cask of Amontillado" didn't quite seem Poean to me.  Having said that, the similarities between the killers in "Cask" and "The Tell Tale Heart" are innumerable as they are undeniable.  Both stories, obviously, are told from the perspective of the killer, and both killers seem (to me, at least) to be clearly insane in that they both have absolutely no reason whatsoever for wanting to kill their victims.  Even with that being the case, however, both narrators work themselves up into an angry frenzy over the smallest imperfection in each of their victims, and in the end they get so mad and self-rigtheous about the whole thing that there's nothing for it but to kill the son of a bitch and wipe him off the face of the earth.  SparkNotes: They're both crazy because they both think way too much and have insane (no pun intended) personal problems.  There is, however, one key aspect in which I see them as differing...Cask of Amontillado's narrator is operating from an almost family-values based mindset, as he cites his families motto that references their refusal to suffer insolence.  He paints it almost as his duty to kill Fortunato...he owes it to his elders, to his family, and to the world, because to him it goes without saying that it is righteous.  So in that regard, this story seems to embody the nature side of the nature vs. nurture debate.  Tell Tale Heart's narrator, however, seems to be slightly more aware of the wrongness of what he is undertaking in that he feels so compelled to justify himself to the reader, always saying "If you think I'm crazy now, you won't when you hear this."  Though he does his best to self-justify, this scenario seems to be a little more lacking of understood righteousness (in the mind of the killer, that is).  Instead, he is operating a little more from a self-indulged and motivated, rampaging perspective, although that certainly works its way into Montresor's motivations as well.  Still, I see this story as subscribing more to the nurture side of things...which of course fascinates me because Poe is the author of both stories.  Thus, I wonder...Nature or Nurture, Poe?