"Okay, if you don't learn something new in this section, I'll give you all your money back.
For people who are still noodling around with the letters and stalling their decision of choosing their best-fit type, here's a reason to get on with it. This area of study plunges one into the deepest exploration of Type imaginable -- but you can't mine it fully until you "own" a Type code!"
So this is a mix of John Beeb's model of Jungian types with transactional analysis. It's not really related to MBTI.