As someone who loves Ruby and Rails, I'm taking advantage of my sabbatical to re-learn these technologies. In the past, I learned just enough to complete a feature, but I also picked up some bad practices along the way, such as bloated controllers and models, not writing tests, and not fully understanding service objects and PORO. To atone for my mistakes, I want to document the errors I made and their solutions as I learn Rails anew. While reflecting on my past projects, I've realized there are many lessons I missed, details I overlooked, and bad practices I need to purge. This article is my attempt to share my experience and help others avoid making the same mistakes.