There is a difference between insomnia and sleeping poorly.
I have been an insomniac all my life, so I feel that I am more than qualified to distinguish between a night of no sleep due to insomnia and a night of really bad sleep.
You see, a bout of insomnia would involve a whole lot of laying in bed and staring at the back of your eyelids (or your slumbering spouse, your slumbering cats, your slumbering dog, the ceiling fan as it rotates, the shadows on the curtains, or generally anything that is in line of sight), and being grossly aware of the fact that you are not asleep. You lay there, ohh so tired, and ohh so very awake. You know you are awake. You know you are not getting any rest. You know there is nothing you can do about it.
Pretty much you know you are scrummed on sleep.
It is frustrating. It is annoying. It is insomnia.
Those who suffer learn to live with it.
Now this is completely different than a bad night of sleep.
At least with insomnia you don't have any delusions of sleep. You are not taunted by mere minutes of sleep. You get nothing.
A bad night of sleep is ohh so much more cruel. Sure it might only be one night, whereas insomnia can be months and months without sleep, but that one night stretches on like some form of ancient Chinese torture.
You actually fall asleep. It seems that everything will be lovely and peaceful and restful, but it isn't.
You find your sleep disturbed by everything.
At first it is something simple like you are too warm. You kick off the covers because you don't want to wake up enough to get up and turn down the thermostat. Only it gets warmer and warmer and you realize you will have to get out of bed. So you sleepily stumble down the hall and make the needed adjustments before crawling back in bed.
As you try and go back to sleep you realize now that you are awake enough to have walked down the hall, you have to pee. So it is back out of bed and to the bathroom. After you find yourself back in bed again you suddenly can't get comfortable. The pillow has turned into an odd shaped lump of clay instead of the soft welcoming thing it should be. You discover that in your short bout of sleep it has given you a kink in your neck and there is no way in which you can lay that is not painful.
After what seems like hours of adjusting you finally get comfortable. Then it happens. Your big toe itches. You think it will pass only to discover it is getting worse. You really don't want to move because you just got comfortable so you sort of rub your toe against the mattress hoping the itch will stop. It gets even worse. Finally in frustration you contort your body to reach down and scratch the offending digit.
And then your ear itches, and then your hip, your knee, your right elbow, the small of your back, your nose, that damned toe again...it just won't stop.
Somehow you finally manage to capture and destroy the traveling itch and you settle back into bed and start to doze off. In your scratching and adjusting time the room has begun to cool down so you tug the covers closer, only you discover the cat is sleeping like a ball of lead on the blankets and it is impossible to actually cover yourself completely. You tug and twist and push as much as you can, yet still you somehow can't manage to get the damn covers out from under what you thought was a six pound cat. You resort in the end to actually booting the cat off the bed so you can bundle up.
Now the cat is awake and more than a little indignant. She begins to yowl. You think maybe she will stop in a minute if you ignore her. It grows louder and more frequent. She is not going to stop. So you yell at her. She grows quiet. You settle back again and are just drifting off, and she starts yowling again. This time after a minute of yowling your spouse bellows at her causing her to silence.
The process repeats another three or four times until you are forced out of bed once more to throw the cat from the room. She proceeds to yowl outside the door, which while now muffled, is still annoying.
Somehow you manage to fall back to sleep. Your dreams are a little disjointed and fitful, but as long as you are asleep who cares. Then suddenly in the dream there is this horrible burning sensation in your chest. The burning grows so strong you wake up only to realize it is heartburn. You fumble around the nightstand for the antacids and pop a couple, grimacing at the wretched chalky taste.
Now that you are awake enough to chew medicine you realize you have to pee again. Another trip to the bathroom ensues. This time as you stumble back to the bed you realize you might have been over zealous when resetting the thermostat earlier, as it is now positively freezing.
You crawl into bed and huddle down, intent on ignoring the cold, snuggling closer to your spouse as you shiver. For a short time this works until your spouse begins to toss and turn in an effort to get comfortable. All of the movement wakes you again. After several of these upsets you decide to brave the cold back on your own side of the bed.
Eventually you give up on fighting the cold and stumble back out to the thermostat and once again adjust the temperature. As you crawl back into bed you realize that the cat took advantage of the open door and has already fallen asleep on the covers. You are left with the choice of sleeping without blankets or repeating the yowling cat exercise from earlier in the night.
You glance over at the clock and realize the alarm will be going off in half an hour, and at this point it no longer matters. You lay back with your corner of blanket and curl in on yourself.
And a miracle happens. You fall into the most peaceful comfortable solid sleep you could imagine. It is so blissfully perfect. You have achieved sleep.
Then the alarm goes off.
Not that I know this from personal experience or anything...