We describe a short, interactive case-based activity for illustrating cognitive distortions of communication underlying resistance to change. Based on a real-life story, the case describes a failed effort by the mayor of Toowoomba, Australia to fund a state-of-the-art wastewater treatment plant. After reading the case, students work individually and in small groups to identify examples of cognitive distortions in the communication between the mayor's office and the citizens of Toowoomba and then suggest better approaches based on evidence-based principles of persuasion. The Wastewater case is both engaging and versatile and has proven popular for students in undergraduate, graduate, and executive education courses. We discuss learning objectives, provide step-by-step instructions for running the activity, describe variations and adaptations for online courses, and include suggestions for debriefing the activity.