I am an INFJ. I have been frequently mistyped as ENFJ, ESFP, INFP, INTP, ESFJ, ENFP, ENTP, INTJ and ISFP. Here's why INFJs are difficult to type correctly, from my personal point of view.
I am a social chameleon
Mirroring was always a more or less natural thing for me. I would adjust my posture to the person I spoke to and naturally sit and move in a way that mimicked the other person, without even thinking about it. My instinctive actions and my movements would typically be adjusted to the group.
I would typically speak about what other people find interesting and make an effort early to adjust my communication to the other person's needs. I would find personal interests that related to the other persons situation. My speech and actions video by video would change depending on who I had talked to that day or what other things had influenced me that day.
2. I play with my personal expression
I constantly review and rehearse what I say. I correct what I say all the time (even during a video) while I search for the right way or the right way to express or convey a certain meaning. When I make videos or write for a certain type, I get completely into that mindset, forgetting my personal mindset or perspective briefly.
3. I would get completely immersed with my message or idea
I basically get into a speaking trance at this point where when I write or speak, it's just a complete flow and words are flowing through at rocket speed. I still maintain a coherent flow however, but the speed at which I think sometimes is confused with extraverted intuition. To me it's just raw immersion in a monologue and letting an idea carry through time uninhibited. Most people shoot down or block their own ideas. I don't.
4. People don't get how I think
People confuse my thought process as logical when it is in fact emotional and social. I think autobiographically and organically rather than factually. I don't go over evidence or proof and I don't give arguments that can be measured as true or false. I deal with social facts and qualitative subjects where the answers often require people to introspect to see nuance rather than measurable evidence.
5. I can become completely detached from my personal self
I speak in general and detached words and often leave out my personal experiences or views. I will often completely forget about these, as I focus on the group I am speaking to or the ideas I am trying to convey. I should become better at conveying my own thoughts, but often, I speak from an outsider perspective, as if I'm the author, but not the main character of the story I tell. This can sometimes confuse my watchers and readers.
6. People exaggerate my creativity
I don't have nearly as many ideas as people think. I listen to and share ideas that I pick up on and I organise and connect ideas that people have. I have a lot of brilliant and creative friends and I try to keep an open mind when other people question me. This allows me to change and adjust to new information, even though the process is stressful to me. It's not a coincidence that this project only became a real thing until I met my ENFP girlfriend. The inspiration I get from her is unreal.
7. People notice I am actually not that intelligent
Truth is, my intelligence is not unusually high, and I don't have higher grades or a more advanced academic background. My merits are modest, not weak, but not strong either. I don't speak like an intellectual or an academic, just a normal person sharing their thoughts.
I grew up in a poor and suburban world where most people only cared about scooters and soccer. This sometimes gets people to type me as a sensor. I just don't think iNtuitives need to be intellectuals, and sensors don't need to be working class heroes either.
8. The more you learn about the MBTI the more you can break the rules
When you start figuring out your own script and how you work, you also learn how to break the rules like an artist. You recognise your limitations but you learn to work around them to overcome situations that you previously couldn't manage. Truth is, type is not a limitation, it's just a stepping stone.
9. I constantly analyse myself
I've asked myself some deep and hard pressing questions all my life. My entire life has been an existential search for who I am and my identity. I have studied myself from many perspectives. I have challenged myself and my own personal view many times. And knowledge changes you.
10. Books have changed me
I read a lot my entire life and when I came across a character I liked, I let myself become a little like that person. I absorbed traits that I found positive and their ideas and emotions and they became a part of who I was. They irrevocably changed me. Books and stories are a little dangerous that way, they can completely alter your sense of self.