"Sonne oder Wolken" (Sun or clouds) is the title of my bachelor thesis. I surveyed the preferences of diffused or directed light. All participants got always two pictures at the same time, one direct illuminated, one indirect illuminated (see pictures below). They needed to decide in all possible combinations of the seven different situations.
I made a book out of this work, you can also find in my portfolio.
The most popular fotography: A naturally lit forest during sunlight.
Long story short: Basiacally most people prefered the direct illuminated scenes. For shure, people prefer beeing in the forest then beeing at the dentist, but in all cases the direct illuminated version won the comparison.
The most unpopular scenery: A dentist in diffused artifical light.
Direct illumination even makes a dentist's surgery more friendly.
The atmosphere has totally changed only by a different light situation.