The view you stop noticing still helps arrange your ordinary mood.

Surroundings keep acting on you after you stop registering them. The wall you face all day, the light that does or does not reach your desk, the strip of sky from the kitchen window are all still adjusting your baseline, quietly, whether or not you can describe the effect. Habituation removes the view from your attention, not from your body. Which means some of your ordinary mood is architectural rather than personal.

Change one thing about where you spend the most hours. Move the chair to face the window, or clear the sightline. Small, and worth trying before assuming the mood is about you.