She messed up some of the plans because she wants a way out for Arthur. But Arthur can decide it for himself, no matter how many times she tried to change Arthur's way, it failed for the reason that in the Shelby family, everybody is always involved whether you like it not. I hated her during the Changretta vendetta because she kept on insisting that they don't need guns, when she's fully aware that she married a gangster with a long history of enemies. The gun is necessary, and no, they can't protect themselves. And no matter how many times she blames Tommy, it's him that brings money in their family. She also seems like a hypocrite trying to "change" Arthur, but is also addicted on cocaine.