I've had problems with sleeping for pretty much all of my life. Mostly related to the fact that I do not get "sleepy" until after 2 or 3 days have passed, and even then falling asleep is difficult. Without medications, mind you.
Since it is so normal to me, I often genuinely forget that most people actually do get sleepy. I start wondering why people want to quit a gaming session because they are tired, until I remember that yes, they actually have brains that send signals saying "need rest, getting sleepy."


