System design can be challenging to learn, particularly because it involves a broad array of knowledge and skills that go beyond writing code. System design requires understanding complex architectures, making informed decisions about technologies and methodologies, and considering factors like scalability, reliability, performance, and maintenance. Here are some reasons why system design might be considered hard to learn, along with tips on how to effectively approach it:

1. Complexity and Breadth of Knowledge

• Wide Range of Topics: System design covers a vast array of topics including databases, networks, caching, load balancing, data sharding, fault tolerance, API design, and more. The broad scope requires a deep dive into many areas of computing.
• Interdisciplinary Knowledge: Effective system design often requires integrating knowledge from various fields such as software engineering, network theory, database management, and sometimes even business understanding, depending on the application.

2. Abstract Thinking and Architectural Vision

• High-Level Planning: Unlike algorithmic problems that often have more concrete steps and solutions, system design requires a high degree of abstraction. You need to envision how different components interact within a system without delving into the minutiae of code.
• Trade-offs Analysis: Decisions in system design often involve trade-offs (e.g., between consistency and availability, speed and cost, scalability and complexity). Weighing these trade-offs correctly requires experience and insight.

3. Real-World Application and Experience

• Experience-Based Learning: Some aspects of system design are best learned through experience. Dealing with real-world problems, understanding user needs, and seeing the consequences of architectural decisions firsthand are invaluable.
• Evolving Technologies: The technologies and best practices in system design evolve rapidly, requiring continual learning and adaptation.

Tips to Learn System Design Effectively:

1. Start with Fundamentals: Before jumping into complex designs, ensure you have a strong grasp of fundamental principles such as how the internet works, what databases are, and basic data structures.

2. Learn Incrementally: Tackle one topic at a time. For instance, start with learning about databases before moving on to learn about caching strategies.

3. Use Case Studies: Study existing systems’ architectures, such as those of Amazon, Netflix, or Google. Many companies share their system designs and the rationale behind their decisions which can provide practical insights.

4. Practical Application: Apply what you learn in small projects. For example, design a simple web application with a database, implement caching, or set up a basic load balancer. Practical application helps in solidifying theoretical knowledge.

5. Online Courses and Resources: Leverage online courses specifically designed for system design such as "Grokking the System Design Interview" or MIT’s System Architecture courses. Books like “Designing Data-Intensive Applications” by Martin Kleppmann are also valuable.

6. Engage with the Community: Participate in forums, attend meetups or webinars, and engage with other learners and professionals. This can provide exposure to diverse problems and solutions.

7. Mock Interviews: Practice with mock interviews focused on system design. This not only helps in preparing for job interviews but also improves your ability to articulate design ideas clearly.

Conclusion

While system design can be challenging to learn due to its complexity and the breadth of knowledge required, it is a deeply rewarding skill that enhances your ability to solve real-world problems efficiently. With a structured approach to learning, practical application, and continuous engagement with the community, you can effectively master system design.