I love this poem because it has so many edges on it. It was written by a then 25 year old Rupert Brooke in around 1912. No one has truly figured it out (does that matter), but it can create many different emotions depending on the reader.
I came back late and tired last night
Into my little room,
To the long chair and the firelight
And comfortable gloom.
But as I entered softly in
I saw a woman there,
The line of neck and cheek and chin,
The darkness of her hair,
The form of one I did not know
Sitting in my chair.
I stood a moment fierce and still,
Watching her neck and hair.
I made a step to her; and saw
That there was no one there.
It was some trick of the firelight
That made me see her there.
It was a chance of shade and light
And the cushion in the chair.
Oh, all you happy over the earth,
That night, how could I sleep?
I lay and watched the lonely gloom;
And watched the moonlight creep
From wall to basin, round the room,
All night I could not sleep.