If you've been following this series, you've already built a strong foundation. We've explored how to identify responsibilities, model domains, apply SOLID principles, choose the right data structures, and think about Low-Level Design from a problem-solving perspective. At this point, it's natural to ask: "If I already know Object-Oriented Design and SOLID, why do I need Design Patterns?" It's a great question. In fact, it's the same question many developers ask when they firs...