When I was younger and still living at home, I often didn't sleep at night. It wasn't because I couldn't, it was just because I preferred not to do so. It was easier for me to get things done at night when the house was quiet, and it was a time when I could do the things I wanted to instead of fulfilling the obligations I had during the day.
My junior year in high school, I had a solid year of good sleep before, sometime in my senior year, I started having awful nightmares and waking up in the middle of the night. I'd be absolutely terrified of absurd things that weren't putting me in danger or circumstances that didn't even exist. I really struggled with this situation, because my boyfriend at the time (who I lived with for most of this period) didn't understand what was going on and didn't really want to. So I'd sit up at night, crying and just generally freaking out while he slept like a baby and had no concern for what was going on. I knew that he couldn't fix the problem, because I didn't have any idea how to fix it, and I didn't expect him to sit up all night with me every night. But I think what I really wanted from him was just some sort of understanding - an acknowledgement that what was happening was a real issue to me, and that, even though he wasn't experiencing it, he understood that it really took a toll on me.
After awhile, I drifted out of that phase and got back into a normal sleep pattern again. I woke up every morning feeling ready to get out and do something new. I took good care of myself and was happy to be making some sort of a life on my own.
Then in 2008, my headaches started getting worse and I had them more frequently. I slept a lot more than normal, because my sleep at night was so disrupted. In 2009, I started having problems even falling asleep. Since then, I've been mostly awake until 4 a.m. every night. I've tried melatonin and Ambien and all of that fun stuff, to no great avail. So at around 11 each night, I get myself ready for bed and usually even try to go to sleep. If I do happen to have such luck, I wake up within an hour or two and can't get back to sleep until early in the morning.
All of this wouldn't be so bad if my body didn't automatically wake up at 7 or 8 every morning. Occasionally, I'll get a nap in before noon or in the early evening, but more often than not, I'm running on 4 or less disjointed hours of sleep a night.
Anyway, I guess my point to all of this is that a lot of people don't understand (either because they don't have the problem and can't grasp it, or they think it's fake, or they just don't care) the effects that constant sleeplessness can have on a person.