I thought it's been understood for a while that the question isn't what you desire or how you behave in groups/alone, but rather "How do you recharge your emotional batteries?"

When I'm in a social setting - with friends or strangers alike, I am gregarious and outgoing. People are shocked when I claim to be an introvert due to my social skills. But the reality is that while I love them and make the most of them, social situations exhaust me. Too many in a row and I dream of a weekend when I can do nothing but play video games, read, or watch TV/Movies.

On the other hand I know people with roughly the same intelligence and social skills as myself who are the opposite. They get antsy on their own, and crave socialization and are clearly the most relaxed in a crowd.