Part of what has always drawn fans to The Witcher, be it the novels, the game, or the new Amazon television show, is the characters. Geralt and all the rest exist in a world that may be at war but is far from black and white. When you add magic and oppression beyond the battlefield there is always more to explore when it comes to motivations, actions, and outcomes.
There are no goody-two-shoes in the Kingdom of Cintra or in any of the surrounding kingdoms either. The sorcerers think they should be in charge, the monarchs think they should be in charge, the common folk are abused by everyone. Since no one in The Witcher is pure and simple here are a few of the worst traits of some of the best characters.
Geralt - His Morals
Geralt wants to believe he is a neutral party. He fights and kills monsters, he has nothing to do with the politics in the greater world around him. He can say he only fights monsters all he wants but viewers, readers, and gamers all know this isn't true. In the world he inhabits it can't be. While fans can respect Geralt for his intended moral com, his claim puts him considerably behind the eight-ball when all hell breaks loose. He should have sought out Ciri long before she reaches him. He was always going to have to pick a side.
Jaskier - Meddling
Jaskier offers a lot of the comic relief both readers and viewers enjoy. It is his curiosity and meddling that often leads to both comedy as well as disaster, particularly for Geralt. If Jaskier had not meddled with the djinn that Geralt found he would not have almost died and (for better or worse) Geralt would not have met Yennefer (at least not then). The bard is too interested in writing an interesting ballad for his own good. He doesn't know when to leave well enough alone and, more often than not, it leads to someone almost getting killed.
Yennefer - Selfishness
Yennefer is clear about what she wants. She wants to be more powerful than anyone at Aretuza or in the world. This often leads to her using and abusing the people around her. She even uses Geralt (see her trying to take the power of the djinn as well as trying to obtain the dragon's egg). Yennefer's power can help many people, but if she sees you as a way to gain more power don't expect any assistance. Yennefer was abused much of her life, it makes sense she would look out for number one, but that doesn't mean it's right.
Ciri - Not Listening
Perhaps it comes with being born to power and riches, but Ciri, despite her brains and power, never did learn to listen. She should have left Cintra sooner but wanted to stay with Calanthe. She should have listened to Dara when he told her he didn't trust Mousesack when he came for her in the forest.
Her not paying attention to the thoughts and needs of others leads to Dara leaving her alone. She's a child, that is understood, but if she doesn't learn to listen she's going to cause a lot more problems for a lot more people very very soon.
Calanthe - Keeping Secrets
As a queen Calanthe was never free to wear her beliefs or feelings on her sleeves, but she held a little bit too much close to the chest, leading, in part, to the fall of her kingdom. If only she had accepted Geralt and Ciri's connection Geralt might have been there when Cintra was attacked. If only she had told Ciri about her destiny sooner perhaps Ciri could have left sooner or at least been trained to protect herself. If only she had spoken with her daughter about who she expected her to marry they might not have fought in front of the whole court.
Tissaia - Classroom Manner
In almost any other world Tissaia would not be allowed to teach. Her classroom manner is atrocious. It's not only that she is stern, but she also seems heartless with her students. She harasses them (Yennefer in particular) and calls them out in front of one another, thus also harming the relationships they might form outside of her classroom. She may be powerful, she may help Yennefer bring other best at the battle of Sodden Hill, but that doesn't make up for who she is behind the closed doors of Aretuza. She is a very hard character to like or .
Triss - Not Asking For Help
Triss is a very capable sorcerer, this is showcased in particular at the Battle of Sodden Hill. Yet, power can also blind many people to their faults and Triss is no exception. Triss's powers make her wait a very very long time before asking for any assistance with the Striga that has tormented the kingdom for many years. Geralt comes out injured but does both defeat the Striga and save the transformed princess inside. How many lives could have been saved if Triss had reached out sooner?
Fringilla - Sides With Nilfgaard
In the Amazon series fans watch as Fringilla comes to power at Aretuza in the same class as Yennefer. She is also sent to Nilfgaard instead of Yennefer and, in the end, sides with the Nilfgaard regime rather than attempting to help her friends and fellow students when Nilfgaard begins attacking the other kingdoms. She helps Nilfgaard succeed at the Battle of Sodden Hill.
Cahir - Killing Indiscriminately
Cahir will grow to be a more complex character as the series continues, but he will always be judged for killing the innocent outside of the battles and war he fought.
When he murdered a tavern full of innocent people in a rage after working with the doppler it showed Cahir at his words, nothing more than a murderer.
Mousesack - Obedient
Mousesack was very loyal to Cintra and its Queen Calanthe. This loyalty and obedience likely led to his own death. If he had stood up to his queen, as her advisor, just a little, perhaps Calanthe would have left the city and lived. Even more important perhaps Ciri would have left Cintra sooner, or Mousesack might even have convinced Geralt to stay.