What stimulates you?
I'm not certain why I'm having so much trouble deciding what stimulates me, but I am!! I think it's because different things stimulate me in different ways. Good conversation can make me excited about ideas, but I think a lot of it is the interaction itself, and that connection with another person - although I guess WHAT we're actually discussing is equally important, because certain conversations really de-stimulate me.
Just the energy between us as we're talking, maybe. That stimulates me. Connection is *really* important. A lot of external things can stimulate me too - when I'm out in nature, I can become overwhelmed with happy thoughts and energy. Same with other physical activities - might just be the endorphins, but moving around and pushing myself physically can often clear my head and energize me to do other things. Music might. I guess for me, I'm interpreting stimulation as something which brings me physical energy, excitement, positive mental/emotional energy..that sort of thing. But all of these things, with the exception of good conversation, are primarily solitary activities. I'm still in my head while I'm doing all of this stuff, even though I might be with people while I'm doing it.
How much external stimulation can you tolerate?
I differentiate between external stimulation in the sense of just ME interacting with the world around me, vs. me interacting with another person or people. With the former, I think I can tolerate quite a bit. With the latter, not as much. Ideally, I'd like to interact with people or do something with others a few nights a week, and then the other nights I'd be perfectly fine on my own, and actually need to just be on my own doing my own thing. But usually, socially, when it rains it pours. I'll either have nothing going on for a week or two, and then I get TOO much alone time (too much alone time is not good - I need some sort of human contact, even if its just a presence, after I'm alone for more than 48 hours - otherwise I get really lonely and want some sort of interaction, and I also tend to get 'stuck' in my head and too wrapped up in my thoughts, and am prone to a downward spiral), or I have something going on 7 days in a row. If I have too much going on, initially, I'm excited about it, because I DO like connecting with people, and I enjoy being with others (assuming I like them ;-). So I can do the extroverted thing, and enjoy it, for maybe 3-4 days, but by day 5 or 6 I really start to emotionally shut down and I get really frazzled. I'll then need a good week or two to fully recover, and in that week or two I don't really want to be around anyone, or do anything. So it's a fine line.....sometimes I can't prevent overextending myself, because, well, sometimes that's just how everyones' schedules line up. But in day to day life, I'll usually 'schedule' two or three days during the week of doing nothing, and one of the weekend days to myself, in between my 'doing stuff' days, just to prevent myself from overextending, and to prevent the need to become a hermit for a week or two.
What is your internal world like?
I guess I'm just ALWAYS thinking about stuff. My life, re-playing social interactions, broader world topics, random things...my brain is rarely not thinking about something. Even when I'm in more of a contemplative state, my mind is still on...it's just in a more mellow state, and it's more just shifting feelings and impressions rather than active thinking.
How much alone time do you need and how often do you need it?
I kinda answered this one already, but I can only do *active* socializing a few times a week - where I'm in 'On' mode, really listening, trying to talk more, and trying to be more of an active conversationalist. I'm not much of a talker. If I didn't *have* to talk and could just ride along with a person or group, without being expected to talk or anything, I'd be able to socialize more often, probably. But then..that's not really socializing. ;-) I'm much more passive, I guess, when it comes to this. I love and crave *company* and being with people and doing things with them, and existing, and sharing whatever might come up, but I don't necessarily need the talking. haha. Um. To further clarify...last year I went to Italy with two of my friends, and prior to the trip I was rather worried that I wouldn't get enough alone time, and I was worried that I'd get frazzled and wouldn't be able to travel with them for 10 days, and always be with them. But...in the end, none of it phased me one bit, because I knew them, we were already comfortable, I wasn't 'expected' to be 'On' and talk...and neither were they...just sharing the experiences and all of that, and us also going off on our own for an hour or so each day if we just wanted to wander alone...it worked wonderfully. So while we were together nearly the whole time...internally I was pretty solitary much of the time, just in my internal world. So externally, I didn't have much 'alone time' at all. But I found I didn't need it. I guess we just traveled well together. It was kinda like the dynamics with my family. I can be around them nonstop and I don't get 'tired' -- but then, all four of us are introverts so although we're together in the same space, we're also separate in our own minds.......
What comes along with being an introvert that most people don't realize?
I don't know? I guess most people do overlook me or wouldn't bother to talk to me because I AM quiet. I'm not the life of the party. It's something I'm really self-conscious about - my quietness - but it's just how I am. It doesn't mean I'm boring or lack interest in someone or something (although perhaps I AM boring, for different reasons, haha) - it just means I'm primarily inside. I like being with people and sharing experiences....but I don't necessarily need or want to talk a lot. And in more casual social interactions, it's a source of uncomfortableness for me..just feeling that I *need* to talk more and should talk more because it's not like the other person wants to have just a one-sided conversation..but my maybe not having anything I really have to say. I don't know. I sometimes think there's a bit of a gender expectation in women, too...women are often portrayed as being the chatty ones, where the man doesn't do much talking, and it seems like it's more 'Ok' for the man to be the quiet brooding type. But I don't often feel that it's 'Ok' for me to be the quiet one. And on some dates, I feel like the guy has been a little unsure of what to do with someone who isn't doing all of the talking. I dunno...maybe that's something I'm putting on myself and I don't need to.
How's that for longest response ever?
Most people would find that enervating, not to mention annoying and depressing.
Any work where my brain takes full control and the external world ceases to be is good, i.e. playing guitar, reading, writing, thinking, watching a movie, drawing, painting, ect.
No, uh... yep, its insane, but in a beautifully sane way, know what I mean. To outside people my thoughts may seem irrelevant and nonsensical, but there is really a crazy well of thought and possibility and all that good stuff. Its like Don Quixote, sometimes I look insane, sometimes I may more sense than anyone you'll ever meet, but I never cease to baffle you with my next move. I've had people describe me much like that, actually 
I really think Don Quixote describes the INFP mind quite well, actually, but not introversion (which is the focus of this thread!). My internal world is full of the classic INFP (enneagram 4, by the way) stuff like imagination, possibilities, emotions, thoughts, random stuff that makes me laugh and everyone goes "whats he laughing about", ect.
), but I will say that I need a lot of it and frequently.
