I have no idea why this guy looks at me like I am insane. every time I have ever talked to him (he doesn't speak or answer me), or been talking near him at work he looks at me with a "you are cray cray" look. But when we see each other across the room he gives me lots of eye contact. WTF?
I should mention it's not in an appealing looking why. it's the brow furrowed one eye brow cocked kinda way. sigh.
This question made me giggle. I know exactly what you mean. I think it's him, not you.
This actually happened to me when I was working. I was ringing up a customer's items and his face had that wide-eyed suspicious look that made me wonder if there was something on my face. Well, he later asked, "you're so pleasant; how do you keep up with that all day?" I was so relieved that he didn't think I was super weird! It was a nice compliment.
So, maybe you're behaving in a way that is striking, and he is handling it weirdly. ;)