In the mid-1980s, Larry Tesler stated that “every application has an inherent amount of complexity that must be dealt with, either in product development or in user interaction”. This adagio is also known as the WaterBed theory and is mostly referenced in product design. However, I believe that it equally applies to any type of “interface” between an author and its consumers, such as UI components, functions, API endpoints, you name it. In this talk, we’ll explore different methods for tackling software complexity, by understanding our users and deciding where to place the effort: in the implementation, or in the consumer.