In order to answer this correctly, extroversion and introversion must first be accurately defined against what is popularly believed.

Introspection.

Unfortunately, pop-psychology has spun their own interpretation of Carl Jung’s extroversion and introversion notions to the point where an extrovert is now known as one possessing an “expressive and socially outgoing attitude” and an Introvert as one possessing a “reserved and socially seclusive attitude”. This has become a very pervasive and commonly held (albeit incorrect) definition of extroversion and introversion.

This wrong interpretation has also led to another unfortunate consequence, which is the notion that being extroverted is what everyone should strive to be. The connotation is that extroverts are fun to be around, get things done, open doors of opportunities for themselves and others and are the movers and shakers of our society. Whereas, if you’re an introvert, well you should probably take a class or two to learn to come out of your shell because the whole world is passing you by.

This isn’t trivial. Since this incorrect understanding exists, is pervasive and because personality tests for employment are based on it, a person can find themselves passed over for a job they were perfectly suited for, given the wrong advice by a counselor, advisor or coach or even pursue an entirely wrong career path.

The Correct Definition of Extroversion and Introversion
Carl Jung defines the notions of extroversion and introversion simply as; "how we relate to the external world".

Introverts prefer the internal criteria for assessing reality. They internalize the external world by weighing things against their own internal gauge and are preoccupied with promoting their own internal “well-being”. Being socially seclusive, shy or reserved has nothing to do with an introverted state of expression.

Extroverts prefer the external criteria for assessing reality. They take the external world at face value since they have no natural internal gauge. They are preoccupied with promoting their own external “well-being”. Being socially outgoing, gregarious or talkative has nothing to do with an extroverted state of expression.

To illustrate the difference between the two, sit an extrovert and an introvert down in a room and tell them both: “You did a great job!” what takes place next are two distinct reactions.

The extrovert will likely take it as “the truth” and walk away with a truly validated sense of competency knowing they did a great job.

The introvert however will walk away pondering and weighing the statement against their own internal yard-stick and may question your reason for making the statement such as: "Did I really do a good job? Are they just saying that to be nice?"

There it is.

Now I can state with confidence (knowing I will be understood) that I am an Introvert.