The work or act of cutting “the world” into categorial units or entities keeps us busy over time and places, whatever the contexts may be – work, family, school… While taking it for granted and convinced of its “naturality”, we usually don’t engage in reflecting upon it. Therefore, we have put the work of categorizing and (binary) coding along with its possible effects in different social and educational work settings at the core of the 2018 Annual Conference of the REFUTS network (Réseau de Formation Universitaire en Travail Social): How do “social” or “pedagogical” workers, “political decision-makers” or “bureaucrats” invent persons as “users”, “recipients”, “clients” or “trainees” by situated categorizations? What are the effects of these categorizations on persons’ lives, in particular with regard to “users/recipients/clients/trainees”? How could we invent social and educational work as a kind of sensitive practice of working with these categorizations and their multiple effects?