Socionics validated that for me.

I'm always late for meet-ups (have pissed some friends off) and lectures (a habit I am getting rid off).

How I know I am INFp instead of INFj:

My room gets messy very quickly and at one time, my bed had books, clothes, stationery, lecture notes and food wrappings on it. Yes, I slept will all that. It was like living in a dumpster. If my friends were to find out about this, they will be really shocked because I don't look like an untidy person. I did a long-dued spring-cleaning a week ago and though this is nothing to some people, it's an accomplishment to me.