Guy's Behavior

Guy always turns his head my direction when I walk pass/behind him, why?

I've noticed its an almost everyday thing. He is usually in the breakroom when I go on break and when I leave for the night and He always sits in the same seat and table everyday (the one closest to the coat cubbie) so his back is facing the coats and lunch bags. I never really payed attention to him being there. Sometimes i noticed him turn but thought he was just moving around. Well today I saw him from the corner of my eye while getting my cup, he turned just his head my direction until I walked off.
Guy always turns his head my direction when I walk pass/behind him, why?
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