Explore the journey of NoRedInk's transition from a typical Ruby on Rails web application to a purely functional stack using Elm and Haskell in this 52-minute conference talk. Discover the motivations behind adopting these technologies, the expected outcomes versus actual results, and the strategies employed for incremental implementation within a mission-critical codebase. Learn about the benefits and challenges of using pure functional languages, including improved error handling and classroom observation capabilities. Gain insights into the risks and rewards of this technological shift, as well as the learning resources available for developers. Examine other experiments conducted and understand the concept of "the opposite of omakase" in software development. Uncover valuable lessons from this real-world production transition to a functional programming paradigm.