For me it was Padme's reaction(or total LACK thereof) after Anakin fully admits to her that he has just slayed women and children(sandpeople)! Are you kidding me? Anakin has just ADMITTED to mass murder of innocent women and children and all she can say is "Everyone makes mistakes" or something to that effect(I can't remember the exact line)? She doesn't feel the least bit creeped-out even?
If someone you knew told you they had just committed several counts of murder for a shaky at best reason, what would you do? In fact, what would ANY normal person do? WTF???? WHO WRITES THIS SHIT?! oh wait, I already know. LOL