How we cite our quotes: (Chapter.Narrator.Paragraph)
Quote #1
I must rest, Maester Cressen told himself. I must have all my strength come dark. My hands must not shake, nor my courage flag. It is a dreadful thing I do, yet it must be done. If there are gods, surely they will forgive me. (1.Prologue.133)
Cressen's technical duty is to serve his lord and the realm as they need him. But his love for Stannis and the belief that Melisandre has an evil influence on him have caused him to forego his duty. Or perhaps he believes killing Melisandre is his true duty?
Quote #2
Tyrion was a little drunk, and very tired. "Tell me, Bronn. If I told you to kill a babe… an infant girl, say, still at her mother's breast… would you do it? Without question?"
"Without question? No." The sellsword rubbed thumb and forefinger together. "I'd ask how much." (9.Tyrion.144-145)
Bronn's duty is to Bronn. More specifically, Bronn's duty is to his bank account. Lords? Honor? Morals? They just get in the way.
Quote #3
Once the maesters in their Citadel had proclaimed the first of autumn, wise men put away a portion of each harvest… though how large a portion was a matter that seemed to require much talk. Lady Hornwood was storing a fifth of her harvest. At Maester Luwin's suggestion, she vowed to increase that to a quarter. (17.Bran.61)
Think it's just peachy being the lord? Maybe it is if you like to micromanage. Bran's duty as Lord of Winterfell is to manage his vassals so they can meet the population's needs, including food and protection.