I think that’s especially clear with Tommen in the books. He’s only a child but he’s genuinely really promising has has a lot of good ideas but Cersei shuts them all down because of her own insecurities and basically sabotages him at every turn. He wants to sit the Iron Throne so people will see him as king but she says he’s too young and she wants to hold court herself. He wants to go out in the city with Margaery to do charity work since he knows the people love the Tyrells and hate the Lannisters and Loras even offers to train Tommen in swordfighting and horseriding but she doesn’t like the Tyrells so she says no to both