Direct sunlight creates great amount of contrast in photographs which gives a harsh contrast to the photographs, which is in most cases creates very unpleasent effect. See the shadow areas, it has lost almost all details. Usually we use fully powered optional flash in the fully sun-lit daylight (which appears absurd for general people) to bring back the detals from the shadow areas and stop the pics from looking too contrasty. It also adds saturation to the photograph. In technical terms, it is called 'Dynamic Range'. Dynamic Range is the difference between the brightest and the darkest shade present in an image. Lower the dynamic range, contrasty an image becomes and vis a vis. Meaning image will look horribly contrasty if the dynamic range is low.