"She is a disease. I regret my role in spreading it." Olenna said to Jaime regarding Cersei just before she died. Cersei wasn't only a disease though, she was one of the smartest women in Westeros that knew what it took to rule the Seven Kingdoms, which is why she outwitted Olenna and all those cunning nobles in the show.

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Her mention raises mixed reactions from fans, but one thing is indisputable, she was the power in King's Landing for the better part of Game of Thrones thanks to her excellent political plays. Cersei's trust in the power of gold and her father's tactics worked for her in the beginning, but her ignorance of the need for humanity was her doom in the end.

Best Of All: Accepting Qyburn's Service

Qyburn named Hand of The queen

With Tyrion gone, Tywin dead, and Jaime not in fighting shape, Cersei was short of powerful people she could trust in King's Landing. Her uncle Kevan wasn't approving of her style of leadership which is why she had to recreate the Small Council in her own image. Qyburn was a smart man with no master and nothing to lose, which is why Cersei could trust him.

He saved her by reviving the loyal monster The Mountain to protect her. Qyburn also helped Cersei take down the Faith Militant and the Tyrells, which effectively left Cersei as the undisputed Queen of The Seven Kingdoms.

Best: Allying With Euron

Cersei and Euron Romance

Euron Greyjoy wasn't the best of men because of his emotional instability, but he was a necessary evil for Cersei Lannister. Daenerys had earned the support of most of the noble houses in Westeros and Cersei didn't stand a chance against her with no alliance.

Euron's ships helped reduce the power of the Unsullied after they occupied Casterly Rock. Euron also helped Cersei ship the Golden Company to Westeros and also took down Rhaegal, weakening Daenerys' forces significantly.

Best: Winning Over The Iron Bank

GOT, The Iron Bank of Braavos and Cersei

Tywin taught Cersei that gold was vital in winning wars. However, under Robert and later, Joffrey, King's Landing was in debt to many people including the Iron Bank. Cersei couldn't buy the support of the Golden Company sellswords without the loan from the Iron Bank of Braavos.

With the gold mines of Casterly Rock dried out, Cersei had to find gold somehow, and who better to ally with than the Iron Bank?

Best: Taking Down The High Sparrow

The Faith Militant at Margaery's Trial

Blowing up the Great Sept of Baelor was one of the worst things Cersei did, but it was also one of the actions that saved the capital from destruction. Cersei tolerated the High Sparrow in the beginning because she thought he was harmless, until he became a threat to civilization.

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He started marching people naked in the streets and raised a militia against the crown in the heart of the capital. The faith militant had turned into a cult and somehow managed to strongarm both Tommen and Margaery into supporting him which meant that King's Landing's secularity was at stake.

Best: Removing Baelish From King's Landing

Littlefinger VS cERSEI

Robert Baratheon's small council was full of cunning and dangerous characters, but none of them was as evil as Petyr Baelish. Littlefinger believed that the idea of a realm was a fallacy and was willing to become the king of ashes as long as he got to sit on the Iron Throne.

While Cersei wasn't exactly the best of queens, she was better than Baelish. Sending Baelish out of King's Landing meant Cersei had one less dangerous man to deal with, even if she didn't realize what a huge threat he posed to her at the time. Her action also sent Baelish to Sansa, another smart woman that gave him the swift death he deserved.

Worst: Killing Ned Stark

Ser Illyn Payne beheads Ned Stark

Eddard Stark was stupid to start a war with Cersei over the paternity of her children, but Cersei was even dumber to leave his fate in Joffrey's hands. Ned's death started the War of The Five Kings, which caused the Seven Kingdoms so much pain.

If she kept Ned alive, Cersei would never have had to worry about an enemy in The North when Daenerys arrived in Westeros. In fact, Ned would have gladly helped Cersei against Daenerys because he had helped Robert and Tywin end the Targaryen dynasty.

Worst: Ignoring Tyrion's Advice

Tyrion VS Cersei Lannister

Cersei's greatest mistake was failing to recognize that Tyrion was her best hope of staying on the Iron Throne. Tyrion always tried to help House Lannister but Cersei never seemed to notice that. He made some mistakes in his quest to secure the future of their house, but his ideas would have kept Cersei and her children on the Iron Throne longer.

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Cersei instead chose to ignore Tyrion's advice not trust too much in the power of gold. Cersei also ignored Tyrion's request to send an army to Winterfell and also decided to kill Missandei even while Tyrion begged her not to do it.

Worst: Ignoring Tommen

Tommen Baratheon jumps to his death in Game of Thrones

After losing two children, it seems like a mother would be very protective of the last surviving one, but Cersei wasn't. When Tommen became king, he had Tywin's protection which meant that no one could rise against him. When Tywin died, Cersei was supposed to be his protection, but she instead made him the victim of her failed political plots.

While Margaery manipulated him, Cersei was too busy mourning Joffrey. When the Faith Militant started controlling him, Cersei was too busy trying to take down the Tyrells and reform the Small Council. She forgot that Tommen was her son and that she needed his name even while fighting her own battles.

Worst: Refusing To Fight The Dead

If Cersei had kept her word by sending an army to fight the Night King, she would have saved both herself and King's Landing.  Her position on the throne was already in jeopardy, and lying to everyone at the Dragonpit Summit made her an enemy of everyone that fought for the living, effectively writing her death sentence.

She couldn't stay on the throne for long without a powerful alliance, and going North to fight for the living would have earned her some sympathy from Winterfell. Cersei instead chose to lie to everyone and start building a precarious alliance with men like Euron which could never hold.

Worst Of All: Killing Missandei

The Mountain Beheads Missandei on Game of Thrones

Cersei literally chopped the head of her last bargaining chip with Daenerys. Missandei was an innocent woman that posed no threat to Cersei, which is why killing her totally uncalled for. She was Cersei's best bet because being Daenerys' friend and Greyworm's girlfriend, Daenerys likely wouldn't burn down the city while she was held prisoner.

Cersei could have used her to negotiate for more time and probably some sort of truce with Daenerys. She instead chose to cut off her head while everyone watched. There was no way Dany and Greyworm could forgive that.

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