We just moved into a new office and one of the best things about it is that we now have small offices and I can keep the curtains closed and the lights off all day. Why would you want more light, especially natural light ? I never open my curtains at home either.
And I can't get enough natural light. I hate artificial light, and require windows anywhere I work. When the temperature is right, I even sit on my back porch to work. For me, sitting in the dark is depressing.
I feel much better in a dimly lit room. Not pitch black but a twilight kind of darkness.
However, I am autistic so that may have something to do with it. I only recently realised this. Ever since I've lived on my own I kept my curtains closed and my room dimly lit, but I never made the link to my autism or sensory issues. It seems kind of obvious in hindsight.
For some reason things that make 'normal' people happy have the opposite effect on me, and vice versa. For example, socialising makes me feel depressed while the more time I spend alone the happier I am. I don't think I've ever felt lonely either.