Roles in Postgres play a crucial role in managing access control, yet they can be complex and confusing for developers used to more traditional user/group distinctions. Unlike other systems, Postgres uses a unified approach where roles can function as both users and groups, which can lead to misunderstandings, especially regarding privileges and role inheritance. This system's flexibility requires a solid understanding of layered privileges across different database object levels, such as clusters, databases, schemas, and tables. Effective management involves using role hierarchies, group roles, and regularly auditing permissions to maintain security. Migration of databases with complex role structures can be particularly challenging, necessitating careful planning and sometimes custom scripts to navigate dependencies and prevent issues. By adhering to best practices like the principle of least privilege and maintaining thorough documentation, developers can leverage the powerful capabilities of Postgres roles while mitigating potential pitfalls.