The most revealing note on Sauron’s character, if you ask me, is a single line in the nigh-unobtainable Parma Eldalamberon 17.* (This is, I believe, the same source where we learn his name had been Mairon before his assortment of unsavory epithets.)
maira noun “admirable, excellent, precious”
Consider how Gollum, apparently spontaneously, not just describes but personifies the Ring.
Consider what term everyone who comes into possession of the Ring eventually uses to refer to it.
“It is mine, I tell you. My own. My Precious. Yes, my Precious.”
Consider what must have gone through Gandalf’s mind when he hears Bilbo address the Ring by the long-lost name that his brother-demigod had borne in the morning of the world.
“It has been called that before,” he said, “but not by you.”
*Thanks Tolkien fandom in the internet age!
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