There's lots of stuff about this around here and this kind of thing interests me, so why not make this as a first chapter?
From my understanding, extraversion is the preference (although, you don't choose; this preference comes from your development, so it could be called an unconscious preference?) of external stimulation while introversion is the preference of internal stimulation. We all have to bump into moments of external stimulation and internal stimulation, so being an introvert does not mean living in your own world entirely and being an extravert does not mean living in the outside world entirely. There is no 100 percent.
I'm an introvert. What are you? (Of course, there are many in-betweens, like ambiversion, ambiverted extrovert, ambiverted introvert, so on.)
Now, there is a lot of things going against either sides, how introverts "need to get a social life" (I'm sorry, I just have a social life that keeps me satisfied, too bad for you. What standard am I matching up for? My own.) or how extraverts "never listen" (Listening is not purely and introverted skill; this is a people skill, and everyone needs it for good communication.). There are things that are fundamentally misunderstood on both sides.
Get this: an introverted and extraverted person's brains are wired differently too. Introverts favor the parasympathetic side of their nervous system, with tends to conserve and regulate energy (so being "socially drained" would make sense; if introverts wanted to conserve social energy, they would search for alone time; they would tend to know when they would need it too), while extraverts favor the sympathetic side of their nervous system which controls fight-or-flight impulses as well as thriving on the release of dopamine, and dopamine motivates humans to seek some kind of external reward as well as tune into their surrounding environment, which is why an extravert has a larger preference for external stimulation.
Introverts also have lower arousal levels than extraverts, so introverts are far more likely to get overstimulated and then have a need to "recharge" in quiet environments. Since extraverts have a higher preference for external stimulation, it would only make sense for extraverts to have higher arousal levels are well.
There is an obvious fine line between introversion and pretentiousness as well as extraversion and obnoxiousness, as the two are sometimes pegged as interchangeable. Not the case. Obviously, there is at least one pretentious introvert and one obnoxious extravert but in my experience, most are not the case.
And what is this about introverts "not having a social life"? Practically everyone has one unless there's someone that doesn't want any interaction at all. Everyone has a social life to meet their social needs. Extraverts may need more people or even less people, and introverts may be the same. This is more relevant to the person than introversion and extraversion.
Having a preference for internal stimulation or external stimulation is not bad. It is who we are. And if someone can't accept it, then that means he or she can't accept who you are and is best not a friend.
