"He is a quiet, shy boy, doesn't mingle too much with people"
"Well, she talks too much"
"Oh my god! you went all alone. Don't you get bored?"
"What do you if you don't party? Is everything fine?
"He is so loud"
"Why do you have to talk all the time. Can't you be at peace with yourself"
And then there are the articles and books that flow around.
"The power of introverts"
"20 signs you are an extrovert"
"Introverts strike again"
"How to connect to people"
"How to be the life of a party"
and it goes on and on.
There have been analyses as to how extroverts perform better in corporate lives, how extroverts spread joy then followed by the power that introverts exert in understanding people, how introverts are more comfortable with themselves and their identity. For some time it was cool to be an extrovert, some time it was intellectual to be introvert, well each one would fit oneself in a box and scorn at the other.
There also are phases when an introvert would be pushed to move on to the other side, an extrovert would wan't to be an introvert because all the "cool" people seem to proclaim so. And in schools, parents with kids who were loners complained their kids didn't mix, people who were not of this category were complained of, that they just picked up trouble every where. One always seems to have a problem with what one has and what one is.
A person can be "normal" and yet not find a need for human company, a person can be "normal" and yet be comfortable with people, a person can be "normal" and enjoy being with people, a person can be "normal" and like solitude, a person can like solitude sometime and not like solitude sometime. All of it is "normal".
I still have a strong hope we all will realize, some day we all will understand that there is a possibility that we fit into the boxes of introverts and extroverts, there is also a possibility that we don't fall into any of those boxes. That is the beauty of being human, probably that's the only one. Some day we shall make peace with ourselves, some day we shall stop defining, some day we shall not find the need to define.