Apart from routine transactions where you have to talk to people, I will talk if I'm in the mood, or I have to out of social necessity or being polite, but usually have to make an effort and never get too serious. If I know the person well I'll talk a more openly. I much prefer my own company overall. I can't see that much I have adds much value to anyone else's life, and few add much value to mine. So, to answer the question, I would not say introvert or extrovert, but non-vert.