Why are people quiet?

Can people live without friends? Can people live without being in society? Some people would rather be friendless then be the most popular kid in his whole class. Is it because the how you were raised? Is it because the events in your life that made you the way you are? What is it? I think the people who are the quiets ones are the ones that have the most sence. Quiet people know about the drama they can get pulled into if they are not careful. So for all the quiet people in the world why is it that your not sociable? Tell me!