The person at the window may be enjoying quiet company with a place.

Being alone and being lonely are different states, and from outside they look identical. Somebody sitting at a window may be having a perfectly good time, in a kind of company with the street, the weather, and the light that requires nothing from them and offers something anyway. Assuming that stillness needs rescuing says more about the observer’s discomfort than the sitter’s.

Ask before you interrupt someone’s quiet, and take the answer at face value. And allow yourself the same thing without justifying it, since sitting still with a view is a real way to spend an hour.