You know you're an INFJ when you fall in love with a concept or fairy tale, and you are absolutely devastated that it cannot exist in our world. Only here: -points at head (or heart... both)-
Thus, you become weary of stories in a way. Why can't it just be? Yet, you continue to ingest them like your life's sustenance.
I never worried about if it could be or not. Read the book 'This Present Darkness,' that is the world I imagine I live in, so really, I am in a truly living fiction of Christianity.
You are more formal in writing than you are in casual talk.
Maybe because in speech I cant collect my thoughts and rely on colliquial speech to speak fast enough to get the ideas out before I lose them, and people understand slang easier than 'smart guy talk.'
When I write, I know my audience is likely more astute in writing ability and can collect my thoughts to use more precise words.
You may or may not have existed as words in a past life. (Idk that was something that happened to me and I found it funny.)
If I existed as words in a past life... it would be a poem written by a drunk Englishman. Maybe the first draft of the 'The Monkey and the Weasel?' children's wong (Which I still think is subtly pornographic by the way.)
People pester me for not doing things that I find unnecessary. This can range from "Why aren't you wearing makeup?" to "Why haven't you put up your Christmas tree yet?" I tend to shrug off a lot of customs or traditions and habits that people have. Maybe that's just me.
I tend to forget them since I don't think about them
My way of thinking, I am still delving into. But in my art class the teacher will ask us why we chose a piece during critique or why we did anything in our own work and I often think, "I picked it because it appealed to me. I created it because that's what I do. I breathe physical life into an idea; I express myself. Must there be any other reason?"
Art is Ideas + Skill + The Will to Express. The only people that need more reasons are cynical NTs and Finns (Well not really Finns, but as a crazy American it feels that way sometimes

).
I find my art is better if I ride on a stream of consciousness while focusing on the quality of the thing presented. I enjoy Salvador Dali's work.
When people tell me that their relative is dying, I can only think, "Huh. Well that sucks." And I have nothing to offer them because I can't feel it. I have other friends like, "zomg I wish there was something I could do!1!" and it is honestly not my first priority. That's what happens. People die.
I haven't cried at a funeral since my mother died. That's not because I'm trying not to or that I'm a heartless monster or anything. If anything, I'm angry. I'm angry at the way things are performed, I'm angry that I can feel the crushing weight of the emotions around me, and mostly, I'm angry that I am expected to cry. I do cry, but it is only the purging of their emotions. I never knew the person I am supposed to be crying for, not truly. I only observe.
You know you're an INFJ when:
You were a kid and played make believe during recess and your classmates thought you were weird.
Me and my INTP friend both!

We STILL play make believe! (we can spend hours making up goofy shit in some RPG world I'm the DM or GM or Storyteller of, and I trust him to not spill the secrets to the other players)
You are cynical about the rest of the world not because you think humanity sucks, but because they won't live up to your standards.
I don't think the rest of the world sucks, I just think the WORLD sucks! So I live in my small one of family, friends, and local surroundings. I would follow politics only to know when to get ready for anarchy and holocaust. In my area, and since I'm in Finland and nothing happens here... I don't follow the news.
Only if I don't know why I was bitten. IF I know why, I adjust my tactics accordingly; sometimes that includes shyness.
The more sad and romantic the storyline is, the more it appeals to you.
Only if it isn't sappy and the reasons for the sadness and romanticalness don't bug me. I thoroughly enjoyed FFXII: Crisis Core's plot and hope to play the rest of the FFXII games to get more of it.
You're moody and intense, but people don't know it cos you seem so calm and collected.
Most of the time
You get very vivid imagery from listening to music, it's like you have Fantasia in your head.
Maybe if you're lucky and have a vivid imagination. Me? Naw, I just get swirls different flavored vibes which is good for me. I also like to sing along... but maybe not so much since now I know what my voice sounds like.... (I got a camcorder recently... I'm a little bit shyer now that I know I don't sound as good as what -I- hear, even
if everyone else only knows the voice I rarely hear

)