I think the fandom is seriously underestimating Sansa's self-control at the purple wedding
She smiles, compliments and encourages all those nobles who participated in her suffering, laughing when she was beaten and stripped, or remaining unmoved when she was forcibly married to a man twice her age who also happened to be her jailer and enemy
She compliments Elinor on her gown, same Elinor who threw her away like dirt, she compliments Lancel on his strength, same Lancel who laughed loudly when she was beaten and stripped
She's so good at it that Kevan and Lancel are beaming and even Tyrion (who regularly called Sansa dumb in his thoughts) is amazed by her courtesy and thinks she would have been a great queen