You probably already know that being an introvert has nothing to do with being shy. But you may not know that being an introvert has nothing to do with solitary book reading or movie watching either — a typical modern representation. Well, at the very least it's not true to the original meaning of the word coined by Jung. Introversion was pretty much redefined down the road to mean withdrawal and aloofness, as opposed to sociability.

Jung defined introversion as an "attitude-type characterised by orientation in life through subjective psychic contents," as opposed to extraversion, "an attitude-type characterised by concentration of interest on the external object." Simply put, introverts are focused on and influenced by the internal (the inside of their mind), while extraverts are focused on and influenced by the external (the outside of their mind, the minds of others).

These were the perfect definitions that should have stayed unmolested. It's sad that Jung himself muddied the waters with his further explanations, saying, for example, that introverts tend to be reserved and cautious, while extraverts tend to be open and daring. While this may be true (there is a correlation), ultimately, it confused people, and they started to use these coincidental traits as the new definition.

I understand this issue not because I've read an article on Wikipedia, but because I feel it. It doesn't matter to me if it's a solitary experience — when I read a book, I can feel the same kind of mental strain I feel midst any other act of focusing on others. Whether I listen to some dimwit at a loud crowded party or struggle with a mediocre novel far away from any living thing, I can feel the same kind of reluctance to engage, like I couldn't care less what their primitive minds can conjure. And even when their minds are far brighter than mine, the reluctance can still be there, with the desire to escape into my own head.

The act of reading usually implies some degree of reflection, and a great deal of imagination, but it's still not an ideal activity to represent true introversion since you still focus on and influenced by the external. Conversely, true extraverts may not enjoy some of the activities where they are assumed to thrive simply because they are the center of attention among a multitude of people. For instance, delivering lectures to large audiences. While there is some degree of engagement with the external (like when you try to read the audience and adjust your delivery accordingly), it is, in reality, mostly introspection: you gather your thoughts, recollect your memories, concentrate on your speech, generate explanations, formulate answers, figure out solutions, etc.

There exists a much better stereotypical representation of an introvert: someone who paints, writes, or composes, especially if they don't try to recreate a real world and instead only reference their inner mind. In other words, they opt for expressionism, not realism.

It's a shame the definitions were altered, because the original ones described something far more fundamental to human psychology, I believe, while the mere desire or tendency to socialize or be loud or be cautious can come and go depending on circumstances.