Do you have your window's blinds/curtains open or closed during the day?

During the day do you open your blinds and/or curtains to let natural light in or do you leave them closed? I’ve noticed some of my neighbors always have theirs closed. Personally, I find that odd because I have to have natural light whenever possible coming into my home. Otherwise, it feels dark and gloomy; dampening my mood.

If you always leave your windows covered, why?

If you like to have them uncovered during the day, why? Do you open your blinds/curtains right when you wake up or later on?

On a side note: do you always have to close your blinds/curtains when it becomes dark? I do, because I feel exposed to people who go by my home.