I apologise for the obviously loaded question. But this does worry me - partly because I have been there a while back.
I am not an MBTI expert but my understanding is that this is simply a tool to help people discover their own and other's preferences. In particular to help you understand other people. It's not designed to define skills, roles, or even really personality (16 categories is a bit of a blunt intrument for that !)
1) The use of 4 pairs of preferences simply does not support the depth that people take this - bearing in mind that everyone is not at the same score of say Introvert/Extrovert etc - It's simply acts as a catalyst for exploring yourself and others.
2) I get concerned that people start to identify with BEING INFJ. Now I understand this. I went through this a while back and it helped me understand a hell of a lot about myself. So I am not knocking it but after a while I really started thinking - ok I know my preferences - what do I do with that? I then started to let go of BEING INFJ and started to work with my skills and preferences - it made a hell of a difference to my life. Note I am not trying to change me to another type, say I don't like being INFJ nor am I disowning INFJ - I simply found that identifying too closely with it as a role rather than preferences was limiting and holding me back
3) yes INFJs might be a tad prone to getting to deep on this!
I really don't wish to hurt/crit anyone here - I am not having a go at anyone - more curious about others' experience.
Does MBTI move you forward or hold you back?