I think the Littlefinger scene was a bit more standard TV fare as you were pretty sure what was going to happen. The showrunners stated they were trying to create all this tension between the Sansa and Arya, but I think everyone knows in their heart that wasn’t going to happen. But I don’t think Sansa actually made up her mind until Arya gave her the dagger. It wasn’t a long con, but long enough.
I did expect Arya to say something about her time in Harenhal and how Littlefinger had conspired with Tywin regarding Rob because it would have been a lot better than her mentioning the true owner of the dagger. Sansa admitting, “I’m a slow learner,” is such a great line I think. It’s her admitting her faults but pushing to persevere anyway.