The right light is critical to good photographs. Both brillant sun with its black shadows and really flat light result in dull boring pictures, especially in black and white. HDR has helped the sunlit images but really flat lighting just plain sucks.
Predicting what light you will have for your photographs can be really difficult. Some photographers will only go out at sunrise but of course sunset lasts just as long and can be every bit as nice. I have found it practical in summer to head out in the afternoon, photograph at sunset, either camp or motel and then go out very early to photograph before and during sunrise, heading home again.
Weather conditions often change though and by not heading out you may be missing on the wonderful light that followed the crap light. A thunderstorm develops and the light is magic. Perhaps you end up photographing something in the shade, with somewhat directional lighting provided by other objects reflecting into the subject area. When photographing the small, local conditions trump overall lighting and even holding up an umbrella, shirt or you can be enough to change the lighting from poor to great.