The prophecy of the prince that was promised ruined the show.
Honestly speaking this stupid prophecy they have made the centre of the show and reason for Alicent claiming the crown for Aegon and Rhaenyra going mad is stupid as hell considering how they adapted the other events. Rhaenyra is incompetent as hell and she believes that she is the prince that was promised it doesn't take much for someone to just that nope no ways even if they haven't read the books or watched Game of Thrones. I think everyone now is looking forward to Rhaenyras death.