What's interesting is relative levels of introversion tend to stay the same. If you went back to your reunion from school, you would probably find that if you ranked everyone in your class into terms of levels of introversion and extroversion you'd still be the same rank.

In our society, the ideal self is bold, gregarious, and comfortable in the spotlight. We like to think that we value individuality, but mostly we admire the type of individual who's comfortable 'putting himself out there.'

Shyness is inherently uncomfortable; introversion is not. The traits do overlap, though psychologists debate to what degree.

Susan Cain Quotes