Ana's team experienced a major incident due to inadequate code reviews on a complex feature change, highlighting the importance of effective code review processes. The text explores various code review methods, including formal reviews, lightweight reviews, and pull request-based reviews, emphasizing the benefits and drawbacks of each. Formal reviews are thorough but time-consuming, while lightweight reviews, such as pair programming and asynchronous reviews, offer flexibility and speed but may lack depth. Pull requests, a staple in modern development, support collaboration and iterative feedback but can become cumbersome with large changes. Stacked pull requests, as facilitated by tools like Graphite, break down large changes into manageable pieces, enhancing review efficiency and code quality without blocking progress. The text suggests that while there is no one-size-fits-all solution, adopting a modern, change-based review process with tools that support stacked pull requests can significantly improve development velocity and accuracy.