This semester, we have one student who came across as unfriendly at first. It was hard to put my finger on why, or on whether it seemed to be more of an aggressive thing or a defensive thing.
It turned out to be a defensive thing, from years and years before she even came to the USA. It had nothing to do with me at all.
Finding this out made it a lot easier for me to interact with her.
But Emily: you’ve never seen it not be a defensive thing. So just go ahead and assume that they’re protecting themselves for a reason that makes sense to them, and act accordingly.