When we connect software systems through APIs, we also connect the people who work on those systems and their contexts. It is a social process that is more important for the fate of the API than the technologies involved in building it. In this talk I will lay out the socio-technical landscape for APIs by discussing factors that influence the relationship between API providers and consumers, such as the alignment (or misalignment) of goals, the mode of communication, the design process, typical points of contention, etc. With this background, I will discuss a number of recurring patterns I have encountered in my career, including the Millstone, the Mountain (or the Volcano), the Rapids (with or without Beaver Dams), and the Sock Puppet. Identifying such patterns is important to better understand and address common challenges, so that we can achieve better outcomes for our APIs.