this reminds me, I did have a good INFj and ESTj friend where I used to live (though I didn't realize their types at the time). When I visited recently all 3 of us hung out and it was sooo chill. Like, no need to "make" conversation, things just flow in the quadra. Of course, we still lack an ISTp (as usual).

LVG, yeah I think there is a lack-of-dual disease! lol.