Introverts give energy when they're with others. When they are out socially, extroverts take energy from them.

This is the reason for the confusion about introverts supposedly not liking people. It's not that we don't like people but we are drained by them and so our rewards are limited relative to extroverts.

When I was a child, I used to hear my very introverted grandfather complain about the "glad-handers" at the Country Club. This is another quality of introverts ... they prefer limited but sincere interactions and consider things like wanton networking and idle chatter somewhere between annoying and pure hell.

Introverts are often alone. They may actually prefer to be alone, behind a closed door. But this doesn't mean they are "lonely" or anti-social.