"I will try to express myself in some mode of life or art as freely as I can and as wholly as I can, using for my defense the only arms I allow myself to use -- silence, exile, and cunning." -- James Joyce
JK Rowling's Greatest Creation
is, I believe, Snape. The way she maintained the tension over his true character for the entire seven books is remarkable. And Harry's gesture regarding Snape at the end (of the last book -- I haven't seen the movie yet) is incredibly poignant.