I guess I can be called an introvert. Here is a very entertaining article about it. Excerpts:
Do you know someone who needs hours alone every day?...Who has to be dragged to parties and then needs the rest of the day to recuperate?
...introverts are people who find other people tiring... Extroverts are energized by people, and wilt or fade when alone. They often seem bored by themselves, in both senses of the expression. Leave an extrovert alone for two minutes and he will reach for his cell phone. In contrast, after an hour or two of being socially "on," we introverts need to turn off and recharge. My own formula is roughly two hours alone for every hour of socializing. This isn't antisocial. It isn't a sign of depression. It does not call for medication. For introverts, to be alone with our thoughts is as restorative as sleeping, as nourishing as eating. Our motto: "I'm okay, you're okay—in small doses."
If we introverts ran the world, it would no doubt be a calmer, saner, more peaceful sort of place.
How can I let the introvert in my life know that I support him and respect his choice? First, recognize that it's not a choice. It's not a lifestyle. It's an orientation.
Second, when you see an introvert lost in thought, don't say "What's the matter?" or "Are you all right?"
Third, don't say anything else, either.