I think I was in middle school the when I took a test to find out my Myers-Briggs personality type. It's the sort of thing they made people do to figure out what career they were best suited for. Hell if I can remember what I tested as, although I can say with confidence that it started with an "I." Well, a lot of time has passed since then, and we have this whole internet thing, so thankfully you can go take a Myers-Briggs approximation online in no time.
This time around I tested as an INTJ. I can't compare that to my younger self, but my guess is that I haven't changed much. Certainly the Judging/Perceiving dichotomy is the most loaded of the four pairs, as that I doubt few people would rather be designated as "judging." But apparently it refers to your preference for structure, which I'll concede that my neuroses require. I think I might have fallen more on the open ended "P" side when I was younger, but I've probably benefitted from the slip (at least professionally). But I wonder if there's a natural personality progression here. Kind of like becoming set in your ways, which for me is the most terrifying aspect of Becoming Old.
Of the four temperaments I'm placed with the Rationals, which apparently are in short supply (6%). That means that 94% of the people out there are irrational, right? Well, at least the description seems to match me pretty well. I do oppose to my specific designation of Mastermind, which of course implies that I should live in an underground lair somewhere. In general I'm in the same bucket as a bunch of boring scientists, but I do take comfort that I have the company of both Hannibal Lector and Gandalf the Grey.