When a customer requests a new feature, it's essential to consider the complexity and potential issues that may arise. Icebergs are features or functionalities that have a significant impact on a project but are not immediately apparent. They can cause problems in three ways: UX designers adding them without understanding their complexity, clients expecting minor changes to be implemented quickly, and users experiencing frustration with seemingly small changes taking a long time to implement. The article highlights the challenges of search, rich text editing, and email processing as examples of icebergs that require careful consideration and planning to avoid project delays and user dissatisfaction. It emphasizes the importance of understanding the complexity of features and prioritizing them carefully to ensure successful project outcomes.