I'd assume other INFJs pick up on these things too because of our Ni, but do you ever notice when a friend is in a new relationship or something and in the pictures people comment "oh you look so happy" but you secretly don't really believe it.
One good example I have is of this girl from my home community that committed suicide. It baffles me how people always commented how "she always was smiling" and "looked so happy". However, when I had initially heard she died I didn't know what the cause was, so I remember looking at pictures of her and seeing how sad and depressed she was deep down. Based on this, I determined that she must have committed suicide, which she had in fact did.
I also see this with people in new relationships where people think they are "so happy" and "in a good relationship" but I see the pictures and think... they're not really in love -- its merely an attraction and they're just having some fun right now but it won't last.
Other INFJs experience this??