The poem
If but some vengeful god would call to me From up the sky, and laugh: "Thou suffering thing, Know that thy sorrow is my ecstasy, that thy love's loss is my hate's profiting!"
Then would I bear it, clench myself, and die, Steeled by the sense of ire unmerited; Half-eased in that a Powerfuller than I Had willed and meted me the tears I shed.
But not so. How arrives it joy lies slain, And why unblooms the best hope ever sown? --Crass Casualty obstructs the sun and rain, And dicing Time for gladness casts a moan. . . These purblind Doomsters had as readily strown Blisses about my pilgrimage as pain.

oh great fun TALLIE HooThomas Hardy - Hap
If but some vengeful god would call to me
From up the sky, and laugh: "Thou suffering thing,
Know that thy sorrow is my ecstasy,
that thy love's loss is my hate's profiting!"
Then would I bear it, clench myself, and die,
Steeled by the sense of ire unmerited;
Half-eased in that a Powerfuller than I
Had willed and meted me the tears I shed.
But not so. How arrives it joy lies slain,
And why unblooms the best hope ever sown?
--Crass Casualty obstructs the sun and rain,
And dicing Time for gladness casts a moan. . .
These purblind Doomsters had as readily strown
Blisses about my pilgrimage as pain.
Hap, byThomas Hardy
I was to analyze this poem (without the author given) in my first exam at Göttingen University, and ever since I have tried to find out by whom it was. Just from working on it for, say 1 hour, I know it by heart, and it has become one of my favourites (apart from some Shakespearean sonnets, that is).
To my imagination it is a lament over the loss of a child, though I cannot prove it from Hardy's biography.