Vibe coding has accelerated software development, but it raises questions about software quality. The author critiques traditional testing methods, highlighting that even extensive testing doesn’t guarantee quality. A humorous analogy illustrates this: a bar explodes despite a perfect beer-ordering system because the engineers failed to consider user needs, like bathroom access after drinking. This points to a broader issue in software development—understanding users deeply is crucial. To address this, the author proposes "vibe coding users." This involves creating detailed user profiles and mapping their interactions with the software. By structuring user information and their workflows, developers can better align the software with actual user needs. The iterative process of vibe coding users and software allows for ongoing refinement. This method suggests that the understanding of users should drive the development process rather than just testing existing software. The approach contrasts with traditional methods like personas and user stories. Instead of building software first and testing it afterward, vibe coding begins with user profiles that act as agents interacting with the software. This shifts the focus to understanding users and their behaviors before any code is written. The author argues that this leads to more intuitive and high-quality software. By simulating user behavior through agents, developers can continuously refine both the user profiles and the software itself, ensuring that the final product meets real user needs.