Edit: 6/9/2015 - Although, I redid the post and made it more of a compare/contrast post, I'm leaving this one up for Jamie's comments on the issue.
When I was growing up, being shy was not considered cool. If you were shy, you were the weird kid (it really doesn’t help when you’re also the only homeschooled kid in the church youth group). People were always being told to be more outgoing, talk more, and participate more. Now, society has seemed to give people the idea that being shy gives you some sort of mystery element, which is termed introvert. It’s perfectly acceptable to call yourself 'an introvert' and not just say you're shy.
Shyness is simply being nervous around people, for a temporary period of time. Introversion is a deeper almost mental situation. Introvert personalities share similar traits with shyness, but introverts may have a hard time coming to terms with the issues that make them the way they are. Introverts (by proper terminology) are people that restrict their contact with other people and pursue solitary activities such as reading, writing, etc. However, I believe that being an introvert goes deeper than being reclusive.
I believe that what really separates introversion from shyness is (and I could be wrong) that introverts simply do not like people at all and avoid being around them, and they're somehow okay with that. They have a hard time interacting with others and tend to have difficulty with social skills. Introverts are deep within their own minds and thoughts, and probably not people who like to talk about themselves. So, if you’re on Facebook and Twitter 24/7 talking about yourself don’t term yourself as an introvert. Introverts are also people that can be difficult to get along with.
If you notice in the movie, when John is around people in the real world, then Charles doesn’t appear. He only comes around when John is lonely, desperate or very stressed. I’m not saying that introversion is caused by schizophrenia or vice versa, but John Nash’s life (at least, how it’s seen in A Beautiful Mind) is real look into the life of a real introverted person and the loneliness they tend to live in.
Other examples of introverts would be Natasha Romanov, Katniss Everdeen and Wanda Maximoff. And that is probably why the term introvert is so popular, because theses characters have made the introverted personality a cool character trait. To be an introvert gives you mystery and edge and almost playing hard to get. What the reality is, is that their introverted personalities have made them miserable. The inability to trust others, to find a reason to laugh or even live, has caused them to live negatively and be afraid all the time. At least in the beginning of their stories; overtime (and with the help of the right people) they begin to see the world differently and slowly come out of their shells.
I also believe is that judging your own unique personality based in this statistic board is a useless waste of time. All it is, is a scientific data that is probably going to change in the next couple of years. An official personality test that isn't to different from the quizzes and tests you take online. Only you can know your own personality type.
Mine is: Silently judging and verbally opinionated while plotting the downfall of society's stupidity. You might think I'm joking, but I'm not! That's only a small part of my personality too. Your personality shouldn't be 4 letters on a board. It's what you see yourself as and also what others see you as. And you need to care about people think about you to. Don't fall into the lie of not caring about what people think about you. You're family and friends are the ones who have to put up with you and their opinions matter. Although, don't end up centering your whole life on what they think. They're are their for moral support and criticism to help mold you into a good person.
What I'm trying to drive home here (and I never write a post about social issues, unless there's a point behind it.), is that saying you're an introvert and being an introvert can be two separate issues and I don't believe that someone can be completely introverted either, they can have other contrasting personalities that help balance their introvertive personality. If you're saying you're an introvert because you believe it's the same or similar to being shy, chances are you probably missed the mark. Also, don't claim to be an introvert just because it's the cool thing to do. Check yourself and ask other people around you what they believe your personality to be. All personalities are different and people can have different traits of introversion and yes, it can be difficult and oftentimes lonely, but the world is not meant to live in alone.