Didn't know that penetrating eyes could be an INFJ trait. When I first met my INFJ, he stared at me so hard that I thought he burned holes in the back of my head, thought it was weird....I returned the favor either because I wanted to assert my self-confidence or because I wanted to see where he was going with it. We've started dating a week ago, and we're kinda already saying the L-word to each other.
Anyway, it's not just the INFJs' eyes that seemingly excrete emotion, it's their gestures, their speech, their facial expressions. At least mine is incredibly easy to read. I can only imagine that it may make him unnecessarily vulnerable at times. But I guess because of that outward expression of his, I find him endlessly fascinating.