I believe that it is all of that. Because they are shy or have social anxiety they prefer more reserved or solitary circumstances.

Being social with strangers or groups sucks the energy out of introverts. Being quiet and alone recharges their batteries

I prefere not to be sociable or go to public places were there alot of people or large crowds. I hate shopping , I am in and out as quickly as possible. I just don't like people . I am an introvert or just weird?

I agree, lots of people do not know the diff and I no longer try to explain it to them. Kinda reminds me of talking to religious peeps.

I do wish that people understood that there is nothing wrong with introversion and that introverts do not need to be fixed.

Good comment. Introversion and extroversion exist on a sliding scale of personality. Social anxiety disorder is a disorder that can greatly change the quality of life and cause misery for the sufferer.

Introversion is a personality trait or type. There is little or no scientific basis for anything more than broad categories.