Who Am I?

The problem with this question is that it has to have an answer but try as I might, I haven't come to a "definition".  I have been told that I'm negative but I generally see myself as a "realist".  Defining myself for me means deciding whether or not I agree with others' perception of me.  I am patient, kind, self-less and selfish to an extreme.  I am witty and argumentative.  I am superficially concerned about somethings that should impact me greatly.  I am high strung and foreboding.  I am physically intimidating but often display false courage and boldness.  I am responsible yet overly involved in matters not of my concern.  I'm lonely even within the crowd.  I have been known to be moody and withdrawn yet exuberant and outgoing in a sporadic pattern.  I consider myself a passionate person often taking on the causes of others but in the same manner a helpless victim to my own perils.  I give and feel unworthy of any returns.  I have been told that I'm strong but I feel that this is a misleading statement as I seem to mostly endure trials rather than fight through them. I'm loyal to a fault and my conscience convicts me for even the most trivial things.  Even with my digits climbing higher and my ways becoming more firmly set, the answer to Who am I is always gonna change.