Turns out asking if the Hat was aware of its own awareness made it self-aware. It explains that it has a huge memory and a small amount of independent processing power, but is generally more like a telepathic mirror that lets children Sort themselves. This leads Harry to worry that taking the Hat off will kill it, but the Hat assures him it is rather looking forward to ceasing to be conscious, and tells Harry that he would not have survived wearing it for more than a few days anyway. It demands that Harry swears not to tell anyone about this incident, so as not to have other children make a game of it.
Harry figures that it can't fulfill its fundamental values (Sorting him properly) without his own cooperation, so he holds his own cooperation hostage to get some answers. The Hat replies that it is a hat, not a god, and warns him that some people may read his mind. It doesn't remember specific children it has Sorted, just a statistical summary of them. It doesn't see any other consciousness under its brim. It tells him that going to Ravenclaw or Slytherin will strengthen his coldness, whereas Gryffindor or Hufflepuff will strengthen his warmth, and points out that Harry respects Hufflepuffs as "the people who do the actual work". Harry refuses to go to Hufflepuff, insisting that going there would sacrifice his potential, which is the very argument that is equivalent to kicking the Hat in the balls.
While Harry is having this argument with a talking hat borrowing his intelligence, the entire Great Hall has fallen silent. McGonagall is panicking thinking about what's going on under the Hat. The Hat finally yells: "SLYTHERIN!"
Harry wishes desperately that he had done something differently to avoid this. The Hat it follows up with: "Just kidding! RAVENCLAW!"
