Bodies are sometimes just so stupid.
For me I guess it's mostly that I want time to myself before having to go but it's annoying nonetheless.

That's the brain being the stupid one.
It's plain stress. I notice it clearly.


Want to know even a more stupid thing?
For me sleeping itself is stressful.
So even if I am dead tired, I get instantly wide awake when I go to bed.
It takes me about half an hour to get to sleep, no matter how sleepy I was a minute before.
My husband always found it extremely amusing - and weird.

I don't find sleeping stressful but I still take more than half an hour to get to sleep.
Husband on the other hand falls instantly asleep the moment he touches the bed.

I think that's quite common? For me it's the time needed to put myself in relax mode. And then sometimes external factors come into play like what time of the month it is or where I am for example.

I love sleep. Sleep is the least stressful part of my day, lol. But it never takes me less than half an hour to fall asleep, and on bad days I can stay awake until I hear the birds start to sing. Just the brain being a stupid meanie, is all.

Well, in my case I was told it's an after-effect of suffering insomnia, that it's pretty common in insomnia patients.
I never thought it could happen in other cases!
Usually people who know me think it's very weird. Nice to see one is not alone.

Wait
The phrase "[they] were asleep as soon as [their] head touched the pillow" isn't an exaggeration?

No, not at all!

My husband used to be like that too!
Until our son was born, then he changed...

Definitely not an exaggeration at all. Husband really does. It's scary.
I wish I could do the same.

@Amura: Maybe we all have insomnia and we don't know.

I don't know about that.
Insomnia is hardly something that can go unnoticed...
When I got diagnosed I had a streak of several days without any sleep at all, and was having allucinations.

It was during my puberty though, never had such an episode in my adult life so I consider myself cured.

I've never had that experience. Always takes at least an hour usually three or four to actually fall asleep