To me, the most compelling photographs are dependent much more upon light than subject matter. Light creates subtle colors, deepening shadows, or sparkling highlights. Light is transitory, changing moment to moment. Flat light can make the most beautiful landscape look dull; unusual lighting can change the simplest or even the homely object into something beautiful.
Whether early morning, late afternoon, or the moments before a storm, a picture is about light. As the light changes even shapes change, adding mystery to the fleeting moment captured.