ISTJ

Well, according to this test I shouldn't be a middle school math teacher. Maybe that's the problem.
Nope. I am not willing to give up so easily.
I am more introverted than extroverted, that's true. (That's the I part in the post's title. It stands for Introvert, Sensing, Thinking, Judging.)
I think there must be a lot of overlap between Sensing and Thinking. They seem to me very much interrelated.
As for judging, yes. I admit it's not the most attractive side of me, but I do tend to make up my mind and stick to my guns. I don't have a huge amount of tolerance or patience for those different from me. You're entitled to make your own decisions, just don't expect me to back you up.
Care to take the test? Follow the link above. Harry S. Truman (pictured) was also an ISTJ. I knew I liked that guy!