This is where I think the real problem is. The problem is not that some people are introverts, the problem is that extroverts don't always try to understand introverts. Too often, extroverts just assume that everyone has the same mindset that they do and they end up harassing introverted people to "get out and be with people" or they will label them as antisocial and avoid them altogether.

Personally, I think of the difference between introverts and extroverts to be kinda like a cat vs a dog. The extrovert is a dog. They are the ones excitedly running up and greeting someone at the door and following them around the house. An introvert is the cat. When someone rings the doorbell, they hide but if you are calm, patient, and don't bother them, they will come out and share a room with you. If they feel like being around people, they will be and when they have enough of social interaction, they leave. You can't chase down a cat and force him to sit on your lap just like you can't leave a dog in his cage for a day. An extrovert's job is to understand and respect that.

When you get an extrovert that does get that, I think friendships and relationship between introverts and extroverts are a natural, beautiful thing. The extrovert offers energy and entertainment while the introvert offers peace and level headedness. My friends are almost exclusively introverts.