Robert Browning's first-person poem, "My Last Duchess," is masterfully loaded with arrogance. The concept of the poem alone reeks of arrogance, as the narrator is bragging proudly about the painting of his "last" duchess, who he had killed.
Here are some of the clearest examples of the narrator's arrogance:
In the fifth line of the poem, the narrator asks his visitor, "Will't please you sit and look at her?" After bragging about the painter for worked busily on the portrait, he is offering the man a seat, expecting anyone would just be delighted to sit down and take in his beautiful painting of his dead duchess.
In line 23, the narrator describes how the duchess was too "impressed" by everyone, and was too nice. "Too easily impressed; she liked whate’er / She looked on, and her looks went everywhere." This suggests that she was sweet and admired by many for her kindness and beauty. This is where it starts to become clear that the narrator killed his innocent, young wife because he couldn't tolerate others appreciating what was supposed to be his.
Later he adds, "She thanked men,---good! but thanked Somehow---I know not how---as if she ranked My gift of a nine-hundred-years-old name With anybody's gift." The narrator feels like his wife was too grateful to others, and therefore disgraced his family's royal name.
Further down, he describes how he could have simply just explained to the dutchess that he didn't like the way she smiled so much at everyone and the other various issues he had with her, but he refused to do so because it would be beneath him: "—E’en then would be some stooping; and I choose / Never to stoop."
"Oh sir, she smiled, no doubt, / Whene'er I passed her; but who passed without / Much the same smile?" The Duke does not feel like she treats him as though he is better than everyone else, which, in his mind, of course, he is.
So he chooses to have her killed:
"This grew; I gave commands;
Then all smiles stopped together. There she stands
As if alive."
At the end of the poem, he simply moves on to show off another precious piece of artwork.