sophie
Break My Heart
As far as super evil villians, I have kind of always wondered stuff like why Sauramon allies with Sauron. He's a wizard, not sure if he's human, but what's he going to do if man is all killed? Just chill with orcs? I never understood it. But maybe he thinks Sauron will let him rule the survivors.
Saruman's flaw, even before the War of the Rings, was hubris. The Istari were sent to Middle Earth to advise and aid the Men and Elves in their battle against Sauron, but not to lead them. Saruman, eldest, wisest, and most powerful of the order always meddled too personally in historical events. In particular, his assumption of the governorship over Isengard is not really the sort of thing the Istari are supposed to be doing. Compare this to Gandalf, who sees a hobbit in need of cultural or personal enrichment through an adventure, and sees a band of Dwarves looking to reclaim their homeland and in need of a burglar to help them, and sees the need in the coming times, to rid Erebor of Smaug and return the region to the hands of Good. Gandalf could drive Smaug out of the mountain himself, or at the least summon an army to assist him. But instead, he puts the dwarves into contact with Bilbo and gives them subtle (or at times not-so-subtle) nudges in the right direction.
Saruman's fall is a result of this hubris. He gets a Palantir and starts communicating with Sauron. Saruman believes all the time that he can manipulate Sauron to unite men and elves and achieve an era of greater prosperity through the Ring. Remember the conversations between the Uruks who capture Merry and Pippin in book 2. They're bringing the ring to Isengard, and not to Mordor (so that Saruman can claim it and then betray Sauron). The problem is that Saruman thereby becomes the classic mark - the guy who thinks he's too smart to get conned by the conman.