Zuko is a fan-favorite character from Avatar: The Last Airbender, and he definitely has one of the most interesting and satisfying character arcs in the series. His redemption arc is widely considered to be well-written and engaging, and in the end, he joins Team Avatar and becomes one of the heroes.
While Zuko learns to have compassion and breaks away from the toxic teachings of his family, he does do a lot of awful things beforehand. This doesn’t mean he can’t be forgiven, but it does prove he was deeply flawed and nuanced as a character.
Accidentally burning Toph’s feet
This instance is high up on this list because it definitely was an accident. However, it showed that Zuko was way too used to reacting suddenly and using fire in a destructive way that could hurt others.
He needed to learn how to harness his fire bending ability so as to not accidentally harm people who didn’t deserve it. Plus, he almost blew his chances at joining Team Avatar.
Lashes out at the people around him
Zuko is only a teenager during the events of the series, and he had a really traumatic life. The way his father treated him was beyond horrible, so he understandably had some unresolved issues.
However, it was still upsetting to see him lash out at the people around him. While he often got mad at Iroh for no reason, he also occasionally got upset at Mai over little things.
Betrays Katara after she tries to help him
At the end of season two, Katara almost heals Zuko using the water from the Spirit Oasis. She is going to help him with his scar, and she shows compassion for him despite everything he’s done. However, Zuko then turns around to betray her as he can’t resist the urge to go back with Azula.
This moment was upsetting because Zuko was so close to doing the right thing, but he just wasn’t ready to give up his desire to be accepted by Ozai.
Breaking up with Mai by a note
Zuko and Mai might be a good couple in some ways, but they weren’t in others. When Zuko left the Fire Nation to join Aang, he broke up with Mai via note. While he might have feared that she would tell others about his departure, it was still a pretty cold way to break up with someone.
This decision understandably upset her, and he could have at least done it in person or explained things better.
Treating Iroh cruelly for a long time
For much of the series, it’s difficult to watch scenes with Zuko and Iroh because Zuko is so mean to him. While Iroh is there for him from day one of his banishment, Zuko takes out his anger on Iroh.
Iroh is always there to help him and encourage him, and Zuko often responds with irritation and even insults. Zuko clearly is struggling internally, but Iroh didn’t deserve this treatment.
Teaming up with pirates
In season one, Zuko makes a bad mistake when he joins up with the pirates in order to capture Aang. In exchange, he says he will bring them back the water bending scroll that Katara took.
The fact that Zuko joins up with such unsavory people shows just how lost he is at the time and that he too is in a very dark place. This choice ends up biting him, however, as they end up double-crossing him.
Stealing the ostrich horses from the family that helped him
The “Zuko Alone” episode is one of the most memorable from season two, and it’s this episode where fans really are shown Zuko’s internal struggle to choose good over evil.
After an Earth Kingdom family takes him in and helps him by offering food and shelter, he repays their kindness by stealing their ostrich horses. It was a really upsetting scene because, once again, Zuko illustrated he knew how to be good, but he just couldn't stick to it.
Betraying Iroh for Azula and Ozai
After all that Iroh and Zuko had been through and after all Iroh had done to help Zuko, it was a total betrayal for Zuko to choose Azula and Ozai over him. Even though Zuko knew that his father didn’t love him and that Iroh did, he still made the wrong decision and let Iroh be captured.
It was one of the worst things Zuko did and also one that made fans angry. Zuko definitely should have known that Azula couldn't be trusted and that Iroh was who he should side with.
Trying to capture Aang and causing so much trouble for Team Avatar
While Zuko might eventually join up with the Gaang and ends up being friends with them, he was their main character at the beginning.
He spent months looking for Aang and trying to capture him, and he wasn’t gentle about it. While he might not have had the same skills in strategy as Azula, he was single-mindedly cruel in trying to capture Aang knowing that his father would kill him.
Is fine with getting Team Avatar killed
While Zuko spent most of his time trying to do the task set to him by Ozai to regain his honor, there were a couple of moments where he tried getting Aang and the others killed.
He went so far as to hire the Combustion Man who very likely could have killed all of Team Avatar. So, while Zuko might have a change of heart later, the group almost didn’t survive him.