I just thought of this: Frodo could not visualize the Shire when the Ring 'controled' him the most on Mt Doom. When the Ring was destroyed, he was sent back into the world he knew, virtually free from what the Ring took from him. Praps when Sauruman saw Isenguard fall so quickly, he realized he was just a wizard fallen from his path. And after the Ring was destroyed, I suppose he might have realized his life was wasted, really, on his dreams. But he took this in spite. Like his long term feeling of when for that moment, those within grasp of the ring felt they coulf fufill their desires with the ring, then realizing they can't. Kind of like Sauruman was drunk for all those years, and then when he was sober, he realized he had done some stupid stuff. [well ive never been drunk or taken a drink-im only 14, so i cant say this from experiance lol]
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Ford Dld Engine Picture