This paper sheds light on some aspects of what contemporary clinical theory calls “borderline” condition providing a description of a key figure of late-modern culture that I will call Homo dissipans (from Latin dissipatio, -onis = scattering, dispersion). Homo dissipans is the opposite of Homo œconomicus, the form that “narcissism” takes on in contemporary “achievement society,” solely concerned with rational action aimed to utility and production. In order to define Homo dissipans, I follow French philosopher, anthropologist, and novelist Georges Bataille’s descriptions of two core phenomena: “excess” and “expenditure.” The former can be defined as a surplus of energy that according to Bataille characterizes human existence, animated by a general movement of exudation and dilapidation and an inexhaustible drive to “pour out” of oneself, especially outside the limits of composure and reasonableness. The latter is an ethical attitude which gives its approval to excess and to its metamorphic and destructive power. The Homo dissipans’ credo is to profitlessly dissipate the surplus of energy, escape into a world of pure intensities in which all forms – including identity – dissolve and surrender themselves to transformation. I argue that Bataille’s ideas about “dissipation” can help us reconsider two features attributed to borderline personality disorder which have been extensively described and sometimes stigmatized – “identity diffusion” and “stable instability” – and to better recognize, understand, and make sense of their phenomenology in the clinical context.