I realize I'm an INFP with an INTJ surface. I'm neither and at the same time I'm both.
As a child I was an INFP, I was always in my own little world and didn't like to talk to people, but loved my imagination and living life free. Eventually the world demanded that I work on Thinking and Judging, around 8 or 9ish. I noticed that I had no one I could rely on other than me. I had to be able to reason clearly and organize things and be aware of my surroundings.
Basically, I never act like an INTP nor an INFJ, but always an INFP or an INTJ. INTJ seems to be more of a hardened shell here to protect the INFP inside.
Rambling on.....does this make sense to you?