I am not entirely certain that the most optimistic of visions is rendered in Freud's work. Freud does a fairly good job exploring how the social construction and manipulation of human beings is one in which human happiness is sediment under layers of control, guilt, repression, and "simmering anger." Freud does not see human happiness enter such a configuration:
One feels inclined to say that the intention that man should be 'happy' is not included in the plan of 'Creation.'
In addition to this, Freud's ending to the work reflects such a reality where happiness is not entirely absolute or at least readily evident. Freud makes it clear that the purest form of Eros will have a difficult time repelling the death instinct, with such a battle defining humanity and social consciousness. Yet, I would pivot to suggest that Freud might suggest that the mere understanding and acceptance of the forces of Thanatos, as well as understanding the condition of social repression that marks being in the world could help to constitute some form of happiness. The case studies that Freud outlines in the work struggle to understand their own condition and why they are the way they are. Through Freud's exploration in the text, "happiness" could be seen as understanding how social reality is constructed and through its development and fortification, the individual's understanding of self is not one of defect and/ or abnormality as much as it is recognizing the impact of one's external setting upon one's psychological consciousness. It is here where happiness, or some semblance of it, might be evident.