Originally Posted by
El_Diablo
She didn't outwit Littlefinger; she and Arya were manipulated by him throughout last season, to the point that they were ready to kill each other. It was only after Bran intervened by sharing the truth about Littlefinger off-screen that the two sisters reconciled (the scene was cut because the showrunners/director wanted to prioritize shock value over storytelling). So she only wised up to Littlefinger because of Bran, but having an all-knowing brother doesn't necessarily make Sansa smart.
She and Littlefinger only saved Jon's rear end in the Battle of the Bastards because she decided to keep that little development to herself, at grievous cost to the Stark/wildling forces. How many of her people were slaughtered needlessly because she didn't tell Jon sooner that they had a potential ally on the way, comprised of forces that were historically allied with the Starks?
Now she is openly antagonizing her primary ally, Daenerys. As Jason noted above, Daenerys should just say, "You won't bend the knee? Oh, really? The Unsullied and Dothraki will be leaving with me and my dragons then." That would shut Sansa up rather effectively, but it goes against the image of Sansa being smart and fierce, so I guess the writers can't let that happen.
I like most of the female characters on this show. I just don't buy the way the writers have decided to make Sansa smart all of the sudden.