During the day in a "real" room, most of the light you see is indirect light.
What light do you see inside the room during a cloudy overcast?
Where is it? And where does it come from?
Where are the shadows, and where do they come from?

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!