One of the neatest things about the Prequel Trilogy is that the character traits which, in any other circumstances, would be virtues end up being the cause of the character’s downfall. Obi-Wan’s dedication to the rules is why he fails as Anakin’s mentor. Padme’s faith in ‘human’ decency and her drive to help others, makes her unable to see the problems of both her husband and the Republic until it’s too late. Anakin’s sense of personal loyalty, need to help, and, most critically, deference to authority, lead him to become Vader. The fact that it’s everyone’s virtues, rather than their flaws, which destroy them make their stories that much more tragic.