That wee-bit heap o' leaves an' stibble
Has cost thee monie a weary nibble!
Now thou's turn'd out, for a' thy trouble
But house or hald
To thole the Winter's sleety dribble
An' cranreuch cauld!
But Mousie, thou art no thy-lane
In proving foresight may be vain
The best laid schemes o' Mice an' Men
Gang aft agley
An' lea'e us nought but grief an' pain
For promis'd joy!
Still, thou art blest, compar'd wi' me!
The present only toucheth thee
But Och! I backward cast my e'e
On prospects drear!
An' forward, tho' I canna see
I guess an' fear!
Rough English translation: 
 Still you are blessed, compared with me! The present only touches you: But oh! I backward cast my eye, On prospects dreary! And forward, though I cannot see, I guess and fear! 
 Still, the mouse is blessed compared to Burns. She can simply keep living in the present, beginning work on a new nest. Burns has the curse of foresight, and of hindsight. He can see the mistakes he’s made in the past and foresee how bleak his prospects are in the future.
To a Mouse