S6E07 Explained – update #2 (Patreon)

"Olenna suggests that Cersei might be “the worst person [she’s] ever met”, and Cersei has done some terrible things – framing the Tyrells, framing Tyrion, having Ros beaten, having King Robert killed, having Lady killed – and that’s just in the show, she does even worse in the books… not to mention her terrible political and economic decisions that damaged the whole realm… and that she’s generally cruel and horrible to the people around her. So some would call it justice that now, she’s lost everything – her power, her prestige, her father, her firstborn, her daughter… in the books, even her brother – and lover – is slipping away. Now all Cersei has left is Tommen, and he’s in the hands of a scheming religious zealot. Really the only card Cersei’s still got up her sleeve is the Mountain – so you can be damn sure she’s gonna use him…"