There's a guy at work who never says hi to anyone, just ignores you if you're ever cordial with him. I thought he was just a jerk or a snob, but it turns out he's just really awkward. I held an elevator open for him once and we got off at the same floor, as we were about to go our separate ways he shook my hand with both of his and promised me a coffee... He's weird. But nice in his own way.