The door to my office is made of mirrored glass – I can see out but passersby can’t see in. From the outside the door is a giant mirror. This simple optical trick makes people forget the logic that doors generally lead to rooms, rooms with people in them. From 9am to 6pm, my office door is transformed into an entertaining parade of strangers unabashedly posing, parading and tweaking, completely unaware that they are being observed.

So when my work gets boring I watch the door instead.

At 11.30am, a smart-looking business man walks up to the entrance. He leans in, peers closely at his reflection and begins to pick his nose with exacting, methodical precision. He is totally absorbed in this task, examining each bogey on the tip of his finger before depositing it into the growing mass of mucus in the palm of his hand.

Someone in my office passes round a pack of chocolate biscuits which we silently eat, watching the stranger as if the door were a cinema screen (or, in this particular case, a zoo).

My colleagues’ mouths curl up and a collective gasp of disgust echoes around the room. The man outside is now inexplicably smearing the bogeys across his chin, mouth and cheeks. The suspense mounts as my manager creeps up to the door and throws it open to reveal a crowd of snickering office workers enjoying the show.

But the man looks through us blankly. Completely unembarrassed, he turns, tightens his tie knot and walks away with powerful, dignified strides.