This heartbreaking poem of Yeats' is my favourite. I love the way you think it's over before its over. The last two lines are almost a bonus. Also the lovely feminine ending, the downbeat at the end is so brilliant.

One that is ever kind said yesterday:
"Your well-beloved's hair has threads of grey,
And little shadows come about her eyes;
Time can but make it easier to be wise
Though now it seems impossible, and so
All that you need is patience."
Heart cries, "No, I have not a crumb of comfort, not a grain.
Time can but make her beauty over again:
Because of that great nobleness of hers
The fire that stirs about her, when she stirs,
Burns but more clearly. O she had not these ways
When all the wild Summer was in her gaze."

Heart! O heart! if she'd but turn her head,
You'd know the folly of being comforted.