Who are you...Who am I?

Have you ever looked in the mirror and realized how nebulous you are?
Not that you, per say, are vague and large or in anyway similar to a nebula, but that perhaps you are not quite as consistent as you think you are.
For instance; I know I am Dan Zubrzycki. I'd like to think of myself as a funny person who can really get out and have a good time at a party, entertain people and have everyone wrapped around my finger because I'm so hilarious.
I'd also know that I am Dan Zubrzycki. I'd like to think of myself as a very serious, reliable, educated and thoughtful person who can debate, read, write and be taken very seriously when i talk because everyone respects my opinion.
However I also know i am Dan Zubrzycki. I'd like to think that i am artistic with a poetic penchant and can be rather eccentric, avoiding social interaction to be alone and more fully understand my art and my mind.
I suppose all of these things are true, personalities are not one consistent, infallible fact about a certain individual, rather an incorporated conglomorate which ebbs and flows, one facet yeilding dominance to another as situations change.
However if you read my peice a few weeks ago you'll have read about the Symbolic interaction theory. In brief it works on the same premise as operant conditioning: That the reaction of society to our actions, eventually determines who we are. A bully is a bully because when he attempts to intimidate, people are intimidated. A class clown is a class clown because when he attempts to be funny, people laugh.
So someone can try to be a bully but if they are not intimidating they will not be effective. One can attempt humor but that doesnt mean they will be funny.
So, as I see it, simply because i believe certain things does not neccisarily make them true. I believe i am a physically tough person with whom you do NOT want to get into a fight with.
I don't know how true that is.
So my question becomes this: are we really what people see us to be? So are the only segments of my personality that are true the ones that other people confirm? In essence does it matter what i believe of myself? For if no one sees certain aspects of your personality does that mean it doesn't exist?
On the one hand Symbolic interactionism does make it seem as though that is the case. What use is something if it is not seen? How true can something be if it is only internalized? We are social creatures (humans) and thrive on our interactions.
Conversely, if i believe myself to be an intellectual that will have a vein in all limbs of my interactions, be they humorous or serious.
Thoughts? Things?