The liminal function of rituals is an expression of the transformative power of the unconscious understood as an ungiven, unexpressed potential to be defined within a series of steps. As the products of the unconscious, therefore, liminality becomes particularly evident in all situations in which the human condition goes through a crisis of definition. Like in the passage rites, the function of relational creativity (with a caregiver, a therapist, or a master ceremonialist) can hopefully lead to a more mature, coherent, and integrated postliminal organization of both the individual and the collective. This paper, through contributions ranging from anthropology to psychoanalysis, figures as a seminal work in the introduction of the concept of liminality into psychodynamic theory and clinical practice. Obsessive Neurosis and Borderline Disorder are two very different mental conditions, yet both highlight the complexity of managing the elements that mark transitions: on the one hand, the compulsory repetition of rituals, on the other, the breaking of boundaries.