For me it was this last episode, S08E03. Til now I have always managed to rationalize stupid stuff that was happening via incredible mental gymnastics and hope of a satisfying ending. But after this episode I don't think there is any hope left. I don't think worthy ending is possible after all the damage done in The Long Night. Even if they somehow bring back the Others and do something good with Bran's story, It won't be able to fix all the stupidity til now. Looking back, I have no idea how I didn't reach breaking point back in season 5.