Loyalty
A Song of Ice and Fire universe places a lot of emphasis on a person's honor. A person is only trusted as long as the person is honorable. Jamie Lannister is called the Kingslayer even though he murdered the Mad King to save the kingdom. The Freys and the Boltons are considered distrustful as they had forsaken the houses they had sworn to protect. Brienne of Tarth struggles with her loyalties. She had sworn to protect Catelyn Stark's daughters but finds herself getting sympathetic towards Jamie Lannister. Cersei also finds a reversal of Fortune as she is betrayed by multiple people as she had herself betrayed a lot of people to get the Iron Throne.
Politics
Westeros has just gone through a civil war for power on Iron Throne. The war left destruction on the majority of continent with the royal treasury in debt. The war had now shifted from the battlefield to paper and minds. Tyrells were trying to get an upper hand by supplying King's Landing with sustenance for winter. Iron Bank had been funding Stannis Baratheon against Cersei. The Faith also gets involved to politics as Cersei enables Faith Militants to carry weapons to enforce the Faith.
Post-war Destruction
A major theme in A Feast for Crows is the post-war destruction. While a war is glorified by the winning side, no one much ascribes to the magnitude of the carnage in the war. Brienne witnesses much of it through her travels to look for Arya and Sansa. She finds a lot of villages have been burned and people have been killed mercilessly.
Revenge
People in the A Song of Ice and Fire universe, even when they are being sensible, are highly impulsive. A majority of their actions are ruled by their desires to avenge acts done against their loved ones. The whole of Dorne seems to be working on that impulse. The people of Dorne already hate Tywin Lannister for the death of Elia Martell. The murder of Oberyn Martell further fueled their bloodlust. Even Doran Martell who seems like the most sensible of all people among Dornish had been nursing a grudge and had been secretly plotting to get Daenerys to support his cause.
Sexual Discrimination
A Song of Ice and Fire universe sees men and women operating in archaic gender roles. Women are mostly used as a tool for marital alliances and to grow one's family line. Cersei Lannister feels strongly against it and tries to rule Westeros as a reagent while Jeffrey and Tommen are on the Iron Throne. She constantly faces opposition from her uncle as well as the people from King's Landing. Brienne of Tarth is constantly chided for wearing an armor and carrying a sword.
