In my particular case, I actually met one of my potential advisors in person. Prior to our meeting, he seemed very interested in me and wrote me an e-mail telling me that I was an impressive student and that I would fit in well with his lab. After the interview, I never heard from him again. Finally, I received an impersonal letter from a dean saying that I had been rejected.
This pissed me off, since I was led to believe by this potential advisor that he was seriously contemplating the idea of taking me on as a student. If he had been more honest from the start, then I would not have had such high expectations. Among other things, I would have applied to more schools. I also think that he could have written me something in person. I mean, it's not like this dude is Einstein or anything (I was admitted into some other programs that are ranked better).