I'm actually really glad I found this thread, because I kinda got into a conversation thing today, and I became very interested in my own reaction that I've been thinking about it all day. So what I'm going to say next is probably more of a recluse thing than an INFJ thing, but I imagine this would apply to at least someone out there, someone who may also happen to be an INFJ, so take this with as much or as little merit as you feel it applies to you.
I think a big problem I find in myself is that, being extremely introverted and as reclusive as I am, I find myself talking to...myself a lot. I don't really spend any substantial time with other humans, but I need some sort of interaction, but with my Ni and Ti being the way they are in me, I found my own thoughts as a good source of conversation. The reason for this being I can see multiple lines of logic in my mind, all of them I perceive as equally valid until I address them, so I can actually agree and disagree with myself on just about anything, whether I'm reading a book, or playing a video game, or thinking of some abstract or concrete idea. These agreements and disagreements are solved nigh-instantly, because I can see both lines of logic, both of which I can physically experience, and thus the discrepancy is resolved quickly. This means that these conversations I have with myself are very pleasant, because through picking apart whatever story idea or visual effect or core mechanic of whatever medium I'm experiencing, I can gain new perspectives without external input, without any extensive or unpleasant/poorly thought-out argument.
Then...then comes other people...
I can empathize with another person's feelings, but I cannot, for the life of me, understand another person's logic that runs contrary to my own. This is a recluse thing that has more to do with a lack of interpersonal skills and low charisma speech checks, but whenever I disagree with someone that I view as important, I am abjectly confused at the other person. My brain is going "Wait, what?! You thi-what?! No! That's wrong! I can tell you with absolute certainty that you're wrong! Here is truck loads of evidence as to why you're wrong (that I can't properly convince you with right now, because I'm a dullard)! The writing is on the bloody wall! It's just over there! Turn your head! I'm so disappointed in you for thinking this way...". That, right there, is the monster and the real problem I have when it comes to interacting with other people: I become disappointed in people easily. I'm disappointed in mankind as a whole, but I really feel that strongly with individuals easily when a different line of logic is encountered that offends me in a major capacity. And you probably can guess why I'm thinking this all in my head; it's because I can't experience that other person's logic firsthand the way I can with my own. I'm so used to having conversations with myself that anyone else's logic becomes a foreign landscape to me. There is, however, one healthy effect that this discrepancy causes, and that is I genuinely want to understand the other person's logic. Even if I feel the deepest reaches of my brain that the other person is wrong, I want to have a calm discussion with this other person about why they think the things they think, but being the socially incompetent fool I am, I'm so taken aback in the moment that I don't know how to have that conversation, so I just move on to other topics that I won't scream internally about.
I'm really trying to work on my social skills, but apparently I'm on the autism spectrum, so the mountain I have to climb is a little taller than most, and instead of bringing climbing gear like a normal person, I brought all the gear necessary for a beach party, though I think that's more of a me thing.
Also, I try to be funny a lot around other people because I want to be entertaining, but that requires a lot of conscious effort because there's nothing funny going on in my head, and I don't get other people enough to know what tickles their funny bone. Again, totally a me thing.