What do Gmail and Slack have in common beyond being among the most loved and used apps in the world? Both were created with a focus on just three key features, which the companies sought to perfect beyond all. Paul Buchheit, who led the development of Gmail, famously wrote about his team focusing on just the ability to search, threaded conversations, and large storage. Similarly, Stewart Butterfield recounts how Slack’s big three features were the ability to search conversations, seamless synchronization, and simple file sharing. In this article, I’ll explain why focusing on just two or three key features is vital to building a meaningfully differentiated and valuable product.