He wanted absolute order under his absolute rule. While Morgoth wanted to destroy the creation of Iluvatar, Sauron wanted to conquer it, and make all of its peoples into slaves like his orcs. He was also a cruel sadist who took pleasure in torture, murder, and destruction. All servants of Morgoth have this trait.
Tolkien, while denying that absolute evil could exist, stated that Sauron came as near to a wholly evil will as was possible. Commentators have compared Sauron to the title character of Bram Stoker's 1897 novel Dracula, and to Balor of the Evil Eye in Irish mythology.
While the book version of Sauron is Pure Evil, due to being a manipulative sadist, which was shown in The Silmarillion, his lack of personality and motives in both the Ralph Bakshi and Rankin-Bass movies renders him not even close to qualifying in those versions.
People say Sauron was that much of a bad warrior, that he got defeated by an Elf and a Man. Well, apparently that Man and Elf were in top 5 best warriors of all times. IIRC in History of Middle-earth it is said none of Children (except maybe Luthien) could match Higher Maiar.
As it turns out, even after forging the One Ring, Sauron was still capable of feeling fear and regret. Actually, even during the War of the Ring and at the height of his power.
Aragorn vs Sauron unreleased scene (better quality) - edited
Did Sauron ever want to be good?
Thus, he completed his fall from a glorious Maiar to the Dark Lord of Middle-earth. The same thing happened at the end of The Lord of the Rings' First Age. For a brief time, Sauron repented of his evils and even sought to heal Middle-earth. Yet, that didn't last long.
"So I think in his pitch to Galadriel, it cannot mean that he loves her or that there's any kind of romantic relationship. There should be no ambiguity around the fact that Sauron is evil — he's terrible, and he's using Galadriel to enhance his power."
Sauron's deepest fear was that Aragorn would use the Ring against him. With its powers of domination, Aragorn could comfortably take over the entirety of Sauron's dark army. Though this would eventually corrupt Aragorn, it would allow him to destroy Sauron and take his place.
Additionally, while he was in his weakened state, Galadriel could hold him off through the power of will alone. However, if Sauron had his One Ring and faced off in a battle against Galadriel, it's unlikely that there would be much she could do.
Meanwhile, a few faithful Númenóreans, led by Elendil, were saved from the flood, and they founded Gondor and Arnor in Middle-earth. Sauron still considered them his hated enemies and he launched a pre-emptive attack on Gondor in S.A. 3429.
Because Sauron lost his Ring, his power severely diminished, and it took him thousands of years to rebuild his power. Even after Sauron declared himself again, his sole focus was on finding the Ring, not on solidifying his dominion.
He wanted absolute order under his absolute rule. While Morgoth wanted to destroy the creation of Iluvatar, Sauron wanted to conquer it, and make all of its peoples into slaves like his orcs. He was also a cruel sadist who took pleasure in torture, murder, and destruction.
Gandalf stated that Sauron feared “something indomitable” within Gollum. By the exact language used, Gollum is indomitable, meaning he cannot be dominated. Sauron is all about domination - and Gollum was openly defiant - breaking under torture, but still openly displaying his hatred and wrath to Sauron.
In his notes, Tolkien remarks that Sauron saw Galadriel as his equal. Add that to the fact that she's untrusting of Sauron (yes, even when he's in his Annatar guise) and an unwavering, single-minded force, and it's more likely than not that Sauron feared Galadriel — or the potential she held to upend his plans.
Sauron seemed to genuinely feel a connection to her, and part of that came from sensing the darkness inside of Galadriel. In that regard, his offer was really a seduction to the dark side.
Saving Galadriel at sea was likely a method of gaining her trust, since Sauron would need an Elf's friendship to enter their realm. Whether he targeted Galadriel specifically because he could exploit her bloody-minded rage and broken heart is unclear.
Morgoth, the first to reign terror upon Middle-earth, was more powerful than Sauron and commanded an army of dragons and Balrogs. While both Morgoth and Sauron were cunning, Morgoth's rule and terror lasted longer and his corruption spread further, making him more formidable in the Lord of the Rings universe.
The answer is, by far, Melkor. Melkor, or Morgoth, wanted to currupt and destroy everything good created by the other Valar. Sauron on the other hand only wanted to control and rule Middle Earth.
Smaug the Dragon had destroyed both the Kingdom under the Mountain and the town of Dale, and Gandalf feared that Sauron might use the desolation around Erebor to regain the northern passes in the mountains and the old lands of Angmar.
Sauron's only interest was an order or to work upon the world in an orderly state, even in the beginning, Mairon really had no love interest. Despite his deceptive attributes, he was a trickster and a seducer, he had little care for attempting to love someone.
After trying and failing to murder Sauron to save Middle Earth in the final episode, Season 2 of The Rings of Power could see Galadriel blinded by rage at Sauron's betrayal and deception. One thing is now certain; the friends, and even potential lovers, have become sworn enemies.
For those that haven't read Tolkien's work, it's easy to see why many audiences suspect Gandalf and Galadriel are in love. After all, many of their interactions in The Hobbit trilogy practically scream romance. However, their relationship remains purely platonic in Tolkien's source material.
