People who don't/can't sleep when they're "supposed to", why? What do you do during this time?

Night time is quiet, no loud talking downstairs, no annoying kids yelling outside, mostly no sirens, less cars = less noise, good time to calm down and think about stuff... stuff like weird philosophical questions and questioning if reality is real, also browsing the web in silence, looking for my next [youtube video / film / tv / anime] to watch.

It's like 6:30 AM here lolz.