Desire is a mental energy. And it is impossible to desire something, something you have not first imagined or seen.
So desire is comparing an image of something and the way it is in reality. That gap is what is called desire.
Now, desire has this imagination element, that shows the object of desire, the finished ‘product’ as if it were already reality. And in that mistake, in that mirage lies the mischief.
Read the original article: More about Desire, And why desire, normally, is a plague