I was reading someone's post a little while back (I think it was Nicole's) about the tendency of some writers to capture and infuse too much of their own personality into that of their character.
I am "guilty" of this approach as well and find it quite hard, at least in the early stages of the creative process, to separate myself from the main character of the work. It is the sense of familiarity, the recognition of feelings, the certainty of expectations - all of which, of course, can lead to predictability and monotony. Without a proper dose of uniqueness, I would create boring and unlikable characters.
The other night, as I was working on defining and developing a proper personality for one of my characters and tried to pull away from too much "me," I asked myself whether I, as an outsider, would actually like myself? If I could step outside my body and view myself as a separate person, observe my actions, engage in conversation, ponder my motivations - would I like me?
The scary part is - I actually had to think about it.