I have one acquaintance from elementary/high school that it turns out is INTJ. I had wondered through the years after discovering MBTI if this past friend might be INFP, but when we were recently reacquainted on facebook I encouraged her to look into type and she turned out to be INTJ.
I had thought she might be INFP because her music tastes are very similar to the INFPs I was familiar with and I have strong memories of her being activist in high school. She created her own newspaper to address her views and then personally distributed it in the hallways.
Now she is a very politically active libertarian. Almost all of her facebook posts are political rants and she talks frequently about how she is preparing for an independently sustainable life and encourages stocking up on gold. I'm pretty sure she thinks the sky is falling. She could be right.
She comes across very strong, but also very bright and clever. When we reacquainted I revealed to her my practically socialist political views and she expressed real interest in understanding my perspectives instead of just blasting them. We did in the end stop communicating because she expressed that she just got too mad reading my perspectives and she didn't want to be mean. I respected her honesty.