Why is it?

Why is it,

That late at night,
After I've put my computer to bed,
Words run through my head,

That while all those I know sleep,
And find rest in their pillows,
I could fill a five year journal,
With verses and thoughts,

That in morning's wee hours,
This is when I am at my best,
Good as the writer,
I always dreamed I could  be,

My husband will look at me tomorrow,
See my bloodshot eyes,
Ask "Rough night?"
And I will reply,
"No I was quite productive",

I have 3 poems to show for it,
And the beginning of some story,
That had been long buried in my mind,

He will shake his head,
And will not understand,
For only writers know,
The time that I speak of,

How we revel in them,
Those inescapable hours,
When words flow so freely,
From the tip of a pen,
That promises creative resolution,

Yet, humor is not lost on me,
When I see,
The irony,
That my computer slept last night,
And I didn't.