Crossing Paths

There's a guy I see near my office all the time. I see him at the place I go to get lunch, I see him walking the streets around my office. Today I saw him in the subway station. He obviously works near me and has the same lunch hour I have. I have no idea who he is and wonder if I will ever know. And then I wonder whether he notices me also and wonders who I am. It's so sad, I don't even know how to stalk him.