This paper investigates how targets respond to treatment that is explicitly or implicitly based on a contextually inappropriate social categorization. In three different experimental studies, a team member appeared to use participants' gender and not participants' personal preference to assign a proofreading task. Targets reported more negative self-evaluations in response to implicit categorical treatment in comparison to explicit categorical treatment. In contrast, explicit categorical treatment increased target's resistance to the treatment received. The pattern of results across the three studies shows that treatment based on a contextually inappropriate category is problematic even when the categorization is ambiguous or associated with attractive and positive outcomes.