A love for detail is a very Poe trait. In The Tell-Tale Heart Poe manifests his flare for detail in the most ironic of ways. The man tries to prove his sanity to the reader by describing the crime of murder to us and he believes that by showing us the intricate detail by which he went about it he must be sane. Now this is the point. You fancy me mad.
Madmen know nothing.
But you should have seen me . It is because of the detail that he went through that we think he is mad. It is odd that someone who is so far gone from sanity would be so cautious and careful. However on closer examination we realize that he is a psychopath and is compelled to act with detail. He thinks that his actions are correct and just and he is convinced of that because his level of caution.