It wasn't easy to complete the entire course, but it was incredibly rewarding once I finished it. I really appreciated being able to learn about design principles and the implementation methods that align with them. Although there were some difficulties because the libraries used in the lectures were a bit outdated and didn't perfectly match the current development environment, I managed by referring to the package.json file in the GitHub source to match versions as closely as possible. For issues that still couldn't be resolved, I took the initiative to solve them using Claude or Gemini. As a junior Java backend developer, taking a proper React course made me realize that the depth of React is no joke. It was also an opportunity to reaffirm why it is so important to have the discernment to choose the right technology based on an organization's human resources and tech stack, rather than blindly following the latest trends. Having completed the course over a long period of 10 months, I find myself reflecting once again on the intensity and hard work of React and frontend developers. I think it's truly amazing, and I sincerely express my respect.