I couldn't stand F.lux the first time either. What I did was set it to where I could barely tell the difference. After a week or so I would find myself thinking

I couldn't stand F.lux the first time either. What I did was set it to where I could barely tell the difference. After a week or so I would find myself thinking "too bluish" staring at my screen at night, at which point I lowered the color temperature slightly. Within two months, I had found a setting I felt comfortable at (right now it's at 3500K).