Attendees came out knowing when certain report types automatically exist, and when they needed to go and create custom report types themselves, along with the many advantages and disadvantages. They also learned about Cross Filters (which is included with Reporting in Enterprise Edition and above, on Sales and Service Clouds)... how you can't see cross filtered information, but you can see the influence of additional object: whether that is Accounts without Opportunities, or Contacts without recent Tasks, or just for deduplication. Last but not least, they also learned about the importance of empowering end-users to create and run their own reports, allowing them to make their own insights on their data, unlocking decision making.