Some of us are less sensitive to it than others. In particular I am prone to migraines in bright conditions, and on a bright summer day I have difficulty lookin

Some of us are less sensitive to it than others. In particular I am prone to migraines in bright conditions, and on a bright summer day I have difficulty looking at the sky, which will be coated in thousands of bright and distracting microscopic floaters * * https://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon https://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon And yes, I'm offering anecdotal data-- but I've already provided the relevant studies so this is just a bonus. In my case, the slightest thing will keep me from sleeping. My A/C was out last night and I got scarcely and hour of sleep because of the heat. I am manic depressive and sometimes I will stay up for days if I don't make extra effort to fall asleep. f.lux particularly made a very noticeable difference to me within days of adopting it.