“Sauron had never reached this stage of nihilistic madness [as Morgoth had]. He did not object to the existence of the world, so long as he could do what he liked with it. He still had the relics of positive purposes, that descended from the good of the nature in which he began: it had been his virtue (and therefore also the cause of his fall, and of his relapse) that he loved order and coordination, and disliked all confusion and wasteful friction. (It was the apparent will and power of Melkor to effect his designs quickly and masterfully that had first attracted Sauron to him.) Sauron had, in fact, been very like Saruman, and so still understood him quickly and could guess what he would be likely to think and do, even without the aid of palantíri or spies; whereas Gandalf eluded and puzzled him. But like all minds of this cast, Sauron’s love (originally) or (later) mere understanding of other individual intelligences was correspondingly weaker; and though the only real good in, or rational motive for, all this ordering and planning and organization was the good of all inhabitants of Arda (even admitting Sauron’s right to be their supreme lord), his ‘plans’, the idea coming from his own isolated mind, became the sole object of his will, and an end, the End, in itself.
[footnote] But his capability of corrupting other minds, and even engaging their service, was a residue from the fact that his original desire for ‘order’ had really envisaged the good estate (especially physical well-being) of his ‘subjects’.”
—J.R.R. Tolkien, The History of Middle-earth X: Morgoth’s Ring, Part V “Myths Transformed” Text VII: Notes on the motives in the Silmarillion (i)