Best mastered albums?

As much as "Hi-Res Audio" matters, I'm starting to realize that the mastering of an album is perhaps even more critical. I'm not 100% sure what mastering is 😅 but based on what I've read, it's the process of "fine-tuning" the recordings before release. Most compilations of high-quality music focus on the file, but few rank by "mastering quality." So, I want your input: what are the best-mastered albums ever? 🤩

Based on my limited understanding of mastering, I've always felt that these albums feel very "polished":

- "Messy" by Olivia Dean
- "When we all fall asleep, where do we go?" by Billie Eilish
- "In Rainbows" by Radiohead