In this episode of "No Stupid Questions," Angela Duckworth and Stephen Dubner explore the concepts of gratitude and forgiveness, questioning why gratitude letters are a common practice while forgiveness letters are not. They delve into the science of apologies, discussing economist John List's framework for optimizing apologies, which includes sincerity, acknowledgment of wrongdoing, commitment to improvement, and a cost to the apologizer. They also discuss the challenges of behavior change, referencing Angela’s "13 commandments" which are divided into three categories: restraining forces, getting going is hard, and sticking with change is hard. They analyze why behavior change is difficult, even with insights from social science, and debate whether more aggressive paternalism or design is needed to promote pro-social behavior.