I have read in this forum that you other INFPs dislike the fact that the person you interact with rubs off on you - positively or negatively.
After some analysis this must be attributed to your two main functions Fi and Ne. They run in kind of a feedback loop. The minor functions are also part of this but to a lesser extent.
Fi is your value set. In contrast to Ti, Fi is fluid. Ever changing. Somebody insulted you? They are on the ignore list. Somebody being helpful, are on the nice person list.
The same person can go from one list to the other several times per day on a good day. =)
Ne is basically a way of finding ways to react to current circumstances. Subconsciously.
The loop goes like this:
Something happens, Fi values it. Ne hints for an evasive path. Path is followed, how we got here is unclear, since it's subconscious. Fi evaluates new position, Ne points out new path etc.
Si can help remember if we were here before and how previous decisions turned out. Te can help to filter Ne's selections in real time to bring some order and predictability to the path finding.
So since both main functions kind of work in the right brain's domain which is not necessarily logical, we do things in a very flexible, intuitive manner adapting to the current situation.
But since we are introverted it's more passive instead of active like for example an ENTP, ESTJ, ESFP, or ESTP would behave. So we are like reflections of our surroundings. Passive instead of active. Stealth fighters? Chameleons? Any other metaphors?
And the final question is. What is this good for? Counseling and analyzing other people for sure.