In the image at left, the foreground is in shadows, although detail can be seen. The eye is drawn to the brighter peak behind. After shooting this picture, I began concentrating on another image in another direction. Sometime later, I happened to look back, and the view had completely changed as the sun slipped lower in the sky and clouds played with the light falling upon the scene. Now the foreground was completely illuminated, and the background peak was cloaked in shadow.
Luck plays an important part in getting good pictures.
It pays to look behind you. Besides catching someone sneaking up on you, you might be missing a great shot. I remember once several years ago photographing a sunrise after a night of rain. After shooting a roll of film, I turned around and saw the most vibrant rainbow I've ever seen arching from horizon to horizon behind me. By the time I reloaded and got turned around, it was fading fast.