Agile methods, especially Scrum, have become staples of the modern software development industry. Retrospective meetings are Scrum's instrument for process improvement and adaptation. They are considered one of the most important aspects of the Scrum method and its implementation in organizations. However, Retrospectives face their own challenges. Agile practitioners have highlighted common problems, i.e. headaches, that repeatedly appear in meetings and negatively impact the quality of process improvement efforts. To remedy these headaches, Retrospective activities, which can help teams think together and break the usual routine, have been proposed. In this research, we present case studies of educational and industry teams, investigating the effects of eleven Retrospective activities on five identified headaches. While we find evidence for the claimed benefits of activities in the majority of studied cases, application of remedies also led to new headaches arising.