What does Poe’s poem show about the power of dreams and the unconscious in our lives?

Poe's poem shows just how powerful our dreams and unconscious can be. The narrator is sleepy, "nearly napping," and it is just about "midnight" when he hears the unexpected tapping at his door. Perhaps the events that follow this are all a dream. He remembers, later, that he was feeling quite sad and "wish[ing] [for] the morrow" and hoping for some relief from his great "sorrow" over the death of his lover, Lenore. As a result of the narrator's depression, it seems that his unconscious mind has taken over his emotions and, if this is not a dream, also his behavior. He fantasizes that it is Lenore tapping at his door, returned to him from the dead. Then, when a raven hops in at the window, he attributes all kinds of strange powers and knowledge to it: he speaks to it and asks its name; then, he seems to think of it briefly as a friend; next, he thinks the bird is a bad omen; then, he thinks the bird might be a gift from God to help him forget his sadness; immediately after, he begins to think that the bird is a prophet of evil or even a devil. His imagination runs riot as a result of his unconscious mind's attempts to deal with his grief. The narrator has himself utterly convinced that the bird is much more than just a bird and that its symbolic "shadow" will cast his soul into darkness for the rest of his life.