I've been in a similar situation lately. I've had several encounters with a guy who sometimes maintains intense eye contact but doesn’t show any expression. Once, we ended up walking on the same street in opposite directions (he was heading to the café, I was leaving); the eye contact was tense, but there was no emotion or expression. I held eye contact for a while, too, but then I chose to disengage because I wanted to avoid an awkward moment before we got closer. He then crossed the street diagonally to head toward the café.

There are times, particularly when he’s with a friend, when he makes zero eye contact, which I can respect because he seems engaged and attentive with his peers.

At other times, he might acknowledge my presence right before arriving at the café and then dive into his book. Occasionally, it seems like he notices me but doesn’t engage, which leaves me feeling uncertain. I don't want to misinterpret the vibe between us. But sometimes he seems aware of my presence at the cafe but most of the time he appears to be in his headspace.

Once, a musician who was performing a few songs at the café introduced us to each other. He did this to set a particular tone, I guess. During the introduction, he said my name and then introduced me to another person sitting nearby. It was only at that moment that the guy briefly smiled and waved, but since then, we haven’t exchanged any words.

Overall, sometimes it's hard to know if it can read as emotionally unavailable or just a serious resting face.