This chapter explores how the intercultural mediation (IM) of translation/interpreting exacerbates cultural differences. Using a survey of 50 professional translators/interpreters (T/Is) and 50 expert users of such services, combined with follow-up focus group interviews, the chapter unpacks the complexities involved in the IM of T/Is. Five main causes of IM failure were identified: Mismatched expectations, lack of power and authority (including mediational authority), cultural misunderstanding, insufficient linguistic and/or thematic knowledge, and contextual constraints. The findings illuminate the key issues surrounding the what, who, and how of IM in translation/interpreting and contribute to their nuanced understanding