very true. nice, it's not that often anymore that i get new insights on functions :/..
yes this makes perfect sense- the reason why i'm so much more easily able to see through INFPs is because of our shared functions (honestly i can spot them from a mile away), but they definitely keep their emotions concealed. i don't know if they react "coldly" to expressions of emotion, but it sure can make them uncomfortable, but yeah- it also makes sense that they long to be "understood" because they don't feel ok about expressing their emotions, so someone who can understand them anyway must seem invaluable. i love it when things "click"

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i still maintain INFJs are masters in disguise, but in a different way. INFJs have a deep inner world of intuitive thoughts, and they only share with people they
really trust. like us, therefore, they tend to wear masks, but for a different reason. INFJs use masks to protect their inner layers, whereas we use masks to express parts of ourselves. they feel comfortable expressing day to day emotions in a regular manner sure, but as Fe is the more "normal" value function, this is in a very regular, and therefore less personal, way. the combination of these therefore means that INFJs often come off as "blank" to those who are just meeting them, when the opposite could not be more true.
i think though, the reason why INFJs are so much harder to read for me is that i can't see my own functions reflected back to me.
INFPs use introverted feeling which is all about keeping your emotions concealed and internalised so although feeling is their dominant function they prefer not to reveal that side to them and can react coldly to the expressions of emotions others make.
INFJs have extroverted feeling as their auxiliary which is still quite regularly used, and this is about body language, exaggeration, facial expressions and being aware of the feelings of those around them. This is why they are good at reading people, their introverted intuition is also very interesting because it gives INFJs and INTJs a sense of what the correct answer is and gives the interesting realisations without them being able to fully explain how they understand something to others.