"some day, some day the earth will be black as tar. some day the earth will be black as tar. and we are gonna see each other the way we truly are"
Sauron after the death of his fair aspect, Annatar. I see in Sauron a miserable, self-abusive and pitiful individual with what was initially arguably, alongside Melkor in the Ainulindalë, a noble goal -self determination, at any cost. The atrocity his aims fell into somewhat invalidates these initial aspirations as a justification for his actions, but I still feel that a good deal of sorrow to see him stripped of his face and contemplating an existence as a shadow of his former self - or possibly a purer expression of what he had become.
I emphasized decay and unchecked deformity to suggest an individual who has lost the motivation to care for appearance - I imagine that after Annatar perished Sauron might very well have fallen into a period of self hatred. At this point the ring, a remnant of his power and original nature, may have become even more important to him.