Introversion - Extroversion or something in between?

I have still not figured out why I cannot stay happy by myself. I always need someone around. It strikes me as selfish because I do not intend to engage them in conversation nor do I want to go out with them. I just need them to be there. The battle then is between an introvert who likes merely a part of the extrovert's world. But it doesn't work that way, does it? What would have Freud thought of such behaviour? Would he have related it to some childhood dysfunction? I think not. He probably would have been contradicted by Seligman with his theory of learned helplessness and Jung would have been mystified with this very overlap of the two concepts he so thoughtfully proposed and which have led to a variety of personality tests to emerge, batantly categorizing people into black or white. What happens if you don't fit neatly into any one category? Do u feel a sense of utter confusion? Maybe that is a matter of perception and also how comfortable one is with ambiguity. Me being very uncomfortable with the latter is perhaps one explanation and probably it is this that caused me to notice this whole introversion-extroversion business. Time to introspect a little more....