Sister-in-law Anne asked a good question. Am I really an introvert?
Twice, Adam and I have taken a Myers-Briggs personality inventory test (once for work, once for going on the mission field). Both times, I tested as a distinct introvert.
Introversion was explained to me this way: it doesn't mean that you can't do the "crowd" thing, even do it successfully. The criterion is -- does it wear you out. Being around any group of people wears me out - is emotionally and physically draining. Saps the energy. I'm enough of an introvert that I MUST have alone time on a regular basis, a fact that drives my clingy, affectionate hubby a little nuts.
I asked an extroverted friend once, how she felt when she walked into a room of, say, 50 people, whom she didn't know very well. She said it was like walking up to a smorgasbord. She just couldn't wait to talk to everyone. Just being there energized her. She left the evening feeling more perky than when she arrived.
All that to say, I can be perky and chatty. But it wears me out. And being in front of 45 teenagers each day has that effect too. I'm energized by being alone.
That, for some reason, sounds rather sad!