* You explain the best practices, but you also explain the bad practices, so I could understand why the improved ones are the best practices. * You explain in detail the trade-offs of development convenience, performance, and maintenance. I haven't experienced much traffic yet, but I was able to understand what backend developers should consider to improve performance when the service grows and traffic increases. * When I worked on improving performance, you showed me SQL queries one by one and explained how performance optimization is done, and also explained that this type of performance optimization is not always a silver bullet. After listening to the explanation of Spring Data JPA and QueryDSL, I feel like I want to solidify my basics of DB and JPA. Thank you for sharing your practical experience in a great lecture :)