"To conclude, programmers work at night because it doesn’t impose a time limit on when you have to stop working, which gives you a more relaxed approach, your brain doesn’t keep looking for distractions and a bright screen keeps you awake."

-- and everyone else in the house is sleeping and can't bug you.

Be very careful with screwing with your sleep cycle. Our bodies and to some extent our minds are hardwired to depend on the natural rhythm caused by daylight/night-time. Obviously this is pretty easy to mess with thanks to artificial light and the cross-over of light spectrums.

There are chemicals in our brains which are only produced by certain rhythms, not to mention the need for sunlight and vitamin D. Being especially hard on your body can be detrimental to your long-term health and when we sleep is almost certainly as important as how much sleep we get.

I write this as someone who has a very tough time on both counts and is seriously envious of his wife who gets good sleep at the drop of a hat.

I think there's a simpler answer they might not have considered. Whatever job I have, I am alway most productive at night. That's because I am nocturnal. I always have been. And the fact is that while I can be at an office early, my mind doesn't function at it's highest capacity until after midnight. Again, this might be an isolated case, but I have a feeling a good percentage of programmers are night owls.

"Because being tired makes us better coders. [...] Similar to the ballmer peak, being tired can make us focus better simply because when your brain is tired it has to focus! There isn’t enough left-over brainpower to afford losing concentration."

Couldn't agree more. I find it easier to design complicated algorithm/architecture at night than I do during the day, even when I'm fully reseted and without distraction.