How many ISTJs have you met that are familiar with MBTI theory? Just sayin'. I still think Ruthie is an xSTJ with a very well-developed Fi (and well-developed Ne).
Ruthie - let me ask you this: do you prefer having decisions finalized (and finished) or being open-ended with them?
My preference is for finalizing decisions. That's making this particular consideration and re-consideration of type a bit outside my comfort zone

. I will say that I see some of the points in SpaceOddity's evaluation, but also a number of holes. For one thing, I often play the role of the skeptic quite naturally, and I don't really see possibilities everywhere - at least not good possibilities. I'm not at all fanciful, and I'm something of a judger in the classic sense of the word - as in, the little internal judge that gavels down one verdict or another on virtually everything I encounter. With the unfortunate exception of work or other practical matters, I'm not a particularly open-ended person.
I really do want to iron out this daydream thing though. Since I was very young, I have had extremely elaborate daydreams that I never share with anyone. As in, I have never ONCE shared them with anyone (hey, the beauty of anonymity). Basically, I create characters and play out scenes in my mind. I'm never a character, and people I know are rarely characters (and if they are, only in very tangential ways). The story-lines can develop for years - I'd say I've probably had about 10 major stories throughout the 30 years of my life, and I don't think I've ever lived a day without spending some time in that world. When I'm in daydream mode, the outside world doesn't exist at all. It's all extremely rich and vivid and complex and also completely separate from the rest of my personality. Unlike the child with the imaginary friend, I never blurred the line between fantasy and reality. That world is entirely divorced from the grounded, realistic - even skeptical - person I am in real life (although I admit, I'll occasionally steal a line or an idea from one of the characters in the daydream without attribution...sometimes I do actually develop theories by working them out through the characters.)
My belief is that daydreaming (especially daydreams in which the person having the daydream isn't even starring in said daydream) is likely the result of an introverted perceiving function, Ni or Si, and that the difference in that function would result in entirely different daydreams. For instance, Ni might create a world that bears little resemblance to the actual world - maybe people don't even look like people, or it exists in the 13th century, or horses fly or something imaginative like that. Si, on the other hand, would likely create a world that neatly overlaps with the real world. Characters do and say realistic things and behave in accordance with the laws of physics. My daydreams are very much the latter.
Problem I'm having is that it seems assumed that daydreams themselves are evidence of N over S. That's just a stereotype, right?
Do you daydream in this way?
Sometimes I feel like I'm trying to type two different people... the external version of me, which seeks an anchor for my life, prefers down-to-Earth people and forms of entertainment, takes a skeptical, judging approach to most things, is generally annoyed by idealism, wants things to be a certain way, and thinks people need to act more in accordance to duty than with subjective, untrustworthy personal values. When I read the temperament descriptions of the SJs, I can check it off point by point as fitting me.
Then there's the internal version, which creates worlds, zones out daily, tinkers with theories, and has a decent amount of personal introspection and insight into others. When I read the standard descriptions of N vs. S, I can check off all the points under N as fitting me. Both versions are authentic - it's not like I'm a dreamy person who
learned how to exhibit skepticism and realism. I've played both roles naturally for my entire life.
Which side am I supposed to think of when typing?