Some people are not lucky enough to have a dark room, hidden from the sun, by each other side of the building. If you are living in the apartment, you are so lucky if you have a room which has a good intensity of sun light. I am not living in the apartment, though, and my dorm room has a good intensity of sun light.
However, I don’t really like if my room illuminated too much by the sun light. I prefer it to be darker inside. I let the sun light comes in, but not too much, I don’t want to be exposed too much by the glare. So, that’s the main reason why I just open the curtain a little bit to avoid the glare.
Sometimes, I prefer to close the curtain and the door to avoid the sun light. I just turn the light in my room. Yes, it relates to external or internal lighting, or whatever. I did it for some occasions, to have a good vision toward my laptop screen for instance (Did I say it correctly?). It really works when I watch a movie in my room.
Hopefully the intangible room inside is not dark. If you get my point, though. Heee heee. *Kidding.