Freud argues that while the mourner knows more or less what has been lost, this is not always obvious to the melancholic. The nature of the loss is not necessarily known consciously, and may just as well involve a disappointment or slight from someone else as the loss of occasioned by bereavement, or even the collapse of a political or religious ideal. If the melancholic does have an idea of whom he has lost, he does not know, Freud says, 'what he has lost' in them. This brilliant point complicates the simple picture of grief. We have to distinguish 'whom' we have lost from 'what' we have lost in them. And, as we will see, perhaps the difficulty of making this separation is one of the things that can block the mourning process.

(Darian Leader "The New Black: Mourning, Melancholia and Depression")