When I first started watching Derren I bought in to a lot of the psychological explanations that he would surrounded his performances with, and they really intrigued me. They intrigued me so much that I went off and bought a book about how to perform mentalist magic (one that was recommended on this very forum)
Now here's the weird part. After I read the book I felt a little annoyed, I felt like I had been tricked, I felt conned, I even felt a little dirty

After a few weeks of brooding about this situation I had another realization, I was angry at a magician for tricking me

I suddenly saw how completely nuts I was being, I was getting annoyed at someone for doing his job, and doing it better then I had ever seen anyone else do it, ever!
I never believed for a second that David Blaine could levitate, I never saw anyone make a woman disappear where I believed it was actually happening, but for a brief moment Derren Brown actually made me believe that I lived in a world where you really could win a bet with a losing ticket, or use blank paper as cash.
Surely a magicians whole job is to instill that sense of wonder in people, where just for a moment you think, Oh my god did he really do that?
I would no more expect Derren to tell the audience how his tricks are REALLY done then I would expect a prop magician to come and stage after a performance and say, "look there's a mirror under this bit, and then theres a trapdoor back here" etc etc.