Window washers see a lot of things while they're on the job. Sure, most of it is probably offices full of people working quietly, but in cases like this one there's a bit more interaction. For the window washer, this might be a common occurrence, but for the cat, this is a mind-boggling phenomenon that must be investigated further.
Only used to seeing the occasional bird fly by, this curious cat can't understand why a human is hanging outside its window. It jumps and swats, but the cat can't seem to reach the human no matter how hard it tries. The window washer, clearly amused, runs his fingers across the glass like a paw and moves on to the next window to greet whatever is waiting for him there.