There's such a lot to say about this
@just me - I don't really know where to begin. For a start there is this:
But maybe even more of a problem is the way the world is split into sensors and intuitives, and it can be even harder to find a meeting ground between these - the normal everyday sensors have even less insight into intuition than extraverts have into introverts. A reason why INFJs can have a hard time of it is because we live in the shadows of the majority of folks we meet, and we live in theirs, and that makes it hard for us to relate to each other in an empathic way. It's very interesting reading
@Enso 's thoughts because mostly we don't come across other INFJs in everyday life and even the other types that we might think are similar are not really. What that means is that, in compensation, we can build our sense of who we are around our seemingly unique perspective, because that's tightly bound up with our self-esteem, and so if we do in fact meet other INFJs, that loss of uniqueness can threaten our identity.
In my own personal experience, there are cliff-edges within people that are hidden in the darkness of our unconscious minds. If we stumble over them, there can be a long fall and a large bang at the bottom, and it's a hell of a climb back up again. My gut feeling is that we are dealing with something akin to energy and that helps to describe what is happening, and even maybe what to do about it, at least as an aspiration. An analogy - we aren't really surprised when someone goes for a 20 mile hike, climbing up and down 5,000 feet of mountain and ends up exhausted. If they did this on an expedition, every day for a month, then we'd expect they'd need several weeks to fully recover their energy, and we wouldn't dream of demanding that someone who has just done that do it all over again without recovering.
The thing is that many of the social situations we find ourselves in are using a different sort of energy at the same sort of intensive rate. We don't have aching muscles when we've used it all up, but we can experience an intensifying emotional distress and an increasing emotional resistance. There is a finite amount of this energy within us, and if we use it up more quickly than we replenish it, eventually something will break, and we fall over a cliff. The trouble is that when we don't understand what is happening, all the 'oughts' start to demand that we keep going, and we feel guilty if we don't and those feelings over-ride the distress. Many of these situations involve accommodating other people, and we feel obliged to them, particularly with those close to us, or our work colleagues, or our dependents.
It helps to understand that we are all finite - to get to know where those cliff-edges are and to keep well clear of them. How to do that? I suspect that in the main those of us who are drawn into excessive commitments to other folks, real or imagined, can only learn through one or two mishaps. It's the same when we learn to walk and talk - we have to learn by trial and error. Having some psychological knowledge helps us understand what has happened and to change the way we manage our emotional commitments, but like all practical skills it needs field experience.
The sort of crisis I described can happen with all types - for instance workaholics have a very similar issue. I think that there are some more specific issues for INFJs though. We grow up relating to other people by bringing them inside us - that's how our Ni works. When we do that, we bring in all their problems and faults as well as their blessings and virtues. This gives us an inbuilt obligation to them and significant empathy with them. We don't realise that other types don't actually relate to people that way and can be much more superficial in how they do it, so we feel bitterly disappointed when they don't reciprocate, but that's like asking a fish to bark!.
We INFJs aren't necessarily competent or wise in the way we do this unless we learn from experience, and it can give us major problems. One of these is that we can confuse our own thoughts and feelings with theirs and we run headlong into inner boundary problems - our identity becomes fuzzy and we start to act and react like the other, even if that isn't the way we really are. It takes a lot of hard work emotionally to do it, and it's very draining of that finite energy pool, though we may think it's infinite when we are young (I did!). If we let it run on too long, the energy runs out like I said before. With INFJs, our unconscious minds can take over at this point and evict the intruder from our core self - this is very likely to result in a sudden cliff-edge crisis and even a complete black-hole shut down of relationship with the other person or people. We can no longer tolerate them within us, but we cannot relate to them without having them in there. There is a skill in letting people in, but not across the inner boundary of our identity, and in consciously controlling how much emotional energy we give to it.
A bit of a ramble so I'll stop there. Fascinating question Just Me.