Oh, who can hold a fire in his hand
By thinking on the frosty Caucasus?
Or cloy the hungry edge of appetite
By bare imagination of a feast?
Or wallow naked in December snow
By thinking on fantastic summer's heat?
Oh no, the apprehension of the good
Gives but the greater feeling to the worse;
Fell sorrow's tooth doth never rankle more
Than when it bites but lanceth not the sore.

Shakespeare, William (1564 - 1616), Richard II