As the OP said: -(ROTS-Mustafar) Anakin's bemused dismissal, when Padme tells him "Obi-Wan knows about us. He wants to help." The look on his face is absolutely unsettling; haughty and borderline psychotic. Absolutely the best acting put forth in the entire saga! He just looks at her and smiles as if to convey that he knows better and he is almost amused at her innocence. "Help me?!" smiles... "he wants to help me alright...he wants to KILL me." And he just smiles almost smugly as if he is almost...bashful to acknowledge how obi-wan is going to regard his murders and atrocious deeds. But he doesn't even correct padme because he knows how far over her head it all is. And he just...smiles. In this moment...his acting is on the exact level as anything ian mcdiarmid has done or could do. The best bit of acting in the saga. In this moment...he IS Darth Vader.