In the 2 examples of houses Joe posted notice how sharp the shadow edges are in the one in direct sunlight.
The Sun is an apparently small light source, because it is 93 million miles away. A built-in flash unit is also apparently small, as is a shoe flash unit.
Apparently small light sources produce harsh light, and sharp shadow edges that don't 'wrap' around the edges.
Notice in the other, overcast shot, the light and the shadow edges are much softer. It's kind of hard to even see the shadows, becuase they 'wrap' around the shadows a lot.
That's because the small Sun is lighting a larger layer of clouds making he clouds an apparently larger light source. In fact massively larger, but there is not as much light, becuase it has been diffused by the clouds.
So photographers often use diffusion panels, light tents, umbrellas, brollyboxes, and/or softboxes to make a small light apperar a lot larger. all sudtio lights are apparently small, unless the light is modifed by diffusion panels, light tents, umbrellas, brollyboxes, and/or softboxes.