Zuko - Loyalty

Thinking about it recently, I realized that throughout his many changes Zuko is consistently a character who values loyalty. He pledges loyalty to his father and maintains it even after being burned and banished. He not only tries to capture Aang, but he even at one point intends to give Aang's staff as a gift to Ozai.

(I suspect the reason Iroh hands the staff to a crewmember rather than taking it to Zuko's quarters himself is jealousy - he certainly doesn't blame Zuko for his continued loyalty to Ozai, but it has to sting a little bit.)

Even after Zuko has come around and given up on being loyal to Ozai, he still values loyalty. He consistently names his betrayal of his uncle as the worst thing he ever did - that Iroh was loyal to him, but he did not return the favor.