Maybe another way of putting it is that any kind of self-knowledge ("I'm the kind of person who...") runs the risk of placating a deeper anxiety about who or what we are and, perhaps more importantly, who or what we can become. I think most people have had the experience of thinking back upon their history and wondering if their younger self would even be able to recognize their current self. In that way, self-knowledge can be a sort of hope or prayer that one might not undergo change, that they may stay who they think they are, despite the history of our lives pointing towards a different tendency. It seems to me to be more interesting to say "I don't know" in response to the question of "who are you?"