Is it possible for a character to be too "real" in a story or should I make them as real as humanely possible?

I think that you should write what you need to write. What you WANT to write. It shouldn't matter WHO the reader is... if you want to write in your own way then you should. Don't change things just to be suitable to certain people. If they don't like it, shame on them. I love this raw kind of writing, its so much more realistic than silly make-believe rubbish that certain people write. *COUGH-TWILIGHT* (;