Red teaming isn't just pen testing. Red team approaches and techniques are used widely in the military, intelligence community, and throughout the private sector. Every institution, from the Marine Corps to pharmaceutical giants, experiences the same organizational pathologies that make them unable to identify blind spots, challenge assumptions, or consider adversarial perspectives. In this talk, I’ll share examples of where red teams were sorely needed (yet not used), where they were authorized (yet failed), and where they actually made a difference. I’ll also offer some "best practices" (an unfortunate phrase) for what tends to make red teams succeed. Some may be useful to the community.