Whatever my actual type is, I am undoubtedly sx/sp. This is fairly certain in my mind. So you can stick that so in your pipe 'n smoke it, thanks.
Let's look at the case for Three:
Strong need to pinpoint and define who I actually am. I feel like a nebulous misty mass of everyone. And to me, that sucks. (I'll discuss Four later.)
Unconsciously acting up a particular part based on how I think that should be. Just look at my entrance to these forums when I tried to tell everyone I was a SEI
Actively working on a particular image I want to project.
And for Seven:
Mach 10 mind. I'm also unreasonably proud of this.
I am a serious quitter. Seriously. I recall moving between enthusiastic and excited to deflated in bored in the span of 20 minutes (when I was working on typing Australian PMs).
I learn things quickly, but generally not in any significant depth. I paraphrase a schoolfriend: "It worries me sometimes when you don't know what I'm talking about. It's so unusual."
I am morbidly afraid of boredom. I'm scared shitless of it. Been there, done that... and I don't want it to happen again.
Related to the above, I have a miracle ability to find something--anything--to do, even if it gets as far as meditating (but this is my Last Resort).
Against Seven:
Why am I still worrying about this after four years? Why don't I go in for "elaborate future planning" or "work"? I don't count being a recreation junkie as "working"--but if the point is just that it's phrenetic activity, I could pay that.
Against Three:
On the one hand, I don't want people to fall in love with an illusion. I don't want that to dilute The Real Human Experience. On the other, I work hard on making a specific impression that serves my own ends. This is confusing for me.
More points:
I'm not ruling out Four. I think it's likely.
I'm a freakin' teenager. This is probably pretty normal.
I forgot what I was going to put here.