React is a black box. Why does that matter?

React, a popular frontend technology, is praised for its small API surface, which can be learned quickly, yet its internal complexity poses challenges. The abstraction model of React, while enabling productivity and focusing on application logic, can create issues due to hidden APIs and the need for a sophisticated understanding of its internal workings. React's outside API, primarily through JSX and functions like `useState` and `useEffect`, simplifies development but can sometimes lead to unexpected behaviors if not fully understood. The internal APIs, especially the reconciliation API, are crucial for React's power but require knowledge and discipline to use effectively. Despite these complexities, React continues to be valued for its ability to provide a joyful and productive programming experience, though it raises questions about whether its abstraction is too opaque, potentially leading to debates and subtle bugs. As React evolves with features like concurrent mode and server components, its complexity increases, necessitating a deeper understanding of its internals to avoid undesired behavior.