Excuse me - I have to ignore you for a while

Here’s a pointed description of one introvert:

"You don’t like having people around, including yourself.”

Not all introverts dislike themselves. For a wonderfully amusing and insightful take on introversion, read Jonathan Rauch’s Atlantic Monthly piece, Caring for your Introvert

For example:

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."

There is some debate on the importance of the introversion/extraversion distinction, though it’s one of the Big Five personality dimensions. Keirsey prefers to talk about Reserved vs Expressive people, but uses similar terms:

Expressive persons appear to be energized, charged up, by contact with other people. Owing to the surge they get when in company, they are quick to approach others, even strangers, and talk to them, finding this an easy and pleasant thing to do, and something they don't want to do without. Such interaction apparently charges their batteries and makes them feel alive. […] On the other hand, Reserved persons can be said to draw energy from a different source. They prefer to pursue solitary activities, working quietly alone with their favored project or hobby, however simple or complicated it may be, and such isolated activities are what seem to charge their batteries. Indeed, the Reserved can remain only so long in contact with others before their energies are depleted.

He closes his comment with an observation that rings true for me:

There is some social bias toward expressiveness in American social life, but Reserved persons have no reason to feel that there is anything wrong with them, and should be sure to provide adequately for their legitimate desire for quiet time to themselves.

The interesting development is that New Scientist reports that the Big Five (conscientiousness, agreeableness, neuroticism, openness and extraversion) may not be set in stone. One research team has found, for example, that openness decreases with age, and agreeableness improves.