I had an interviewer express extreme approval every time I answered a question, complement me on me AS A PERSON based on subtleties he saw in me and my application, and laugh at some of the things I said. By far my best interview. That was the only school I interviewed w/ that rejected me. FWIW I don't think I mentioned to them that they were my first choice.
All I'm trying to say is... don't expect anything. I walked out that day 99% sure I had just earned a spot at my dream school. I was accepted into really great schools on December 1st, but I'm only just now recovering from a bout of depression.