It isn’t because the setting is not photo-worthy, nor down to the time of day or people walking past. It is all because of you (or me, if you prefer). Taking a photography trip, working on a full day production, or too many consecutive hours of shooting can leave you feeling frazzled and mentally drained . . . so it’s important to take regular breaks.
This is something often overlooked in photography – as it is such a creative and diverse field, photographers will often forget that even for them it’s necessary to distance yourself from time-to-time and think about other things!