I agree - that's why I concluded that these extremes might be regarded as generally pathological, an obstacle to be overcome. That's also why I can't take the concept of ambiversion very seriously insofar as being a special state of existence goes. I'm thinking ambiversion would probably include most well-balanced individuals, and, well...I don't think extroversion or introversion are bad things, they simply denote a preference. I think it's possible to be a non-anxious, friendly introvert just as much as I think it's possible to be a mellow, downtempo extrovert. We've come to lean so heavily on stereotypes that we're tossing out a new buzzword to cover the ground that doesn't fit the exaggerations that we've previously imagined.
I agree with this, actually! It's not that I'm regularly left feeling dissipated and exhausted from interaction with other people. It's more accurately that, after a while, I start jonesing pretty hard for some time alone to go do what
I'd like to do. I'm definitely not taking a nap when the party's over; I'm just having fun writing, listening to music, adding movies to my "must see" list, working on some other random project - anything by myself. My energy levels are naturally very high and I sleep somewhat little.
I do have emotional barrier issues that
can drain me a little bit, but I think it's somewhat unrelated to introversion in and of itself. Being around others feels a bit like being one of the eggs in a frying pan wherein all of the yolks have broken and spilled into each other; I can't keep others' emotions safely outside of myself. If there's any unhappiness, any stress, any pain, I feel it very viscerally and then am overwhelmed by a simultaneous desire to help the other person
while also wanting to run away from it, as quickly as possible. That can certainly be tiresome, but usually I'm pretty good at foreseeing and dodging those situations before they arise. If not, I keep my cool and be strong for the other person...but then I'm definitely gonna want to treat myself, BY myself.
So when it comes to everyday people interaction, I don't feel like my
batteries will automatically need to
recharge.

I simply would rather go do my own thing later, because I like being alone. It makes me happy. As in, it sure was fun dancing with you, sir; don't call me, I'll call you, k thanx bye.
It's a misleading parameter, the whole "recharge" thing.
I can relate, but I am more of a cognitive functions girl, myself. I think the dichotomies can be a good way to start, but I also find they can foster some of the stereotypes we're struggling with here.
For me, introversion hasn't meant anxiety. It has meant a preference for space, a lack of need for attention, and overall self-containment. I do have anxiety, but it's generalized and genetic - not social. People hardly shake me at all anymore, at least insofar as my self-confidence and worry for their opinions are concerned, but perhaps that might be due to my extremely unpleasant experiences growing up. Exposure therapy by accident, what didn't kill me made me stronger, etc. I'm not very worried about what people think, but I do care how they feel (and there certainly is a difference).
I get pretty tired of the idea that introverts simply can't deal with other people - that we're all just phobic and anxious - but sometimes anxiety really is a factor. And as much as I get annoyed with these relatively common assumptions about introverts and anxiety, I just want to say that your reasons here are totally valid, and I'm not trying to undercut them at all. Anxiety is a truly awful thing to grapple with.
Yes! The enneagram can be a big player in this game, too. My type combination probably looks like a joke to most people - and I understand why they might think so - but for me, it explains the duality in my personality better than anything else does. I'm an only child, and I was raised in an area where I literally had no neighbors to interact with. My parents were often unavailable in some way, so I learned as early as possible that I could get what I needed if I entertained myself. The pattern stuck; I like being busy, creative, and mentally active, but I'm cool with my ability to be all of those things on my own - even if I'm exploring a new city by myself. The only person I've ever been able to tolerate in large doses is my boyfriend (ISTP).
I'm happy that finding your enneagram type seems to have helped!
And I agree that there are certain tendencies that seem to give better I/E cues. Reticence? Gregariousness? How often does the individual seek attention or feedback from others? How often do you make the first move with others? If you're bored, will you find something to do on your own, or would you prefer to be bored with a friend?