How one communicates concerns about another person's actions or performance can significantly affect both the extent to which the feedback improves behavior as well as the quality of the ongoing relationship with the feedback recipient. This article reviews evidence-based principles for delivering corrective feedback and describes an engaging classroom exercise designed to help Organizational Behavior students learn about and apply these principles. Students are presented with a set of dilemmas written as letters to a fictitious advice columnist, "Dear Obby" (pronounced "OB"). The letters, describing situations that call for corrective feedback, can be student-generated or provided by the instructor. Teaching tips are included to help instructors use the scenarios to generate discussion about the goals and principles of effective feedback and to give students opportunities to practice feedback skills in role-plays.