Sandor Clegane, AKA The Hound, is one of the most fascinating characters on Game of Thrones. When we meet him, The Hound serves as Joffrey's lackey and will do anything to appease his King. Well, almost anything.
As we soon learn, The Hound has certain thresholds, and crossing said thresholds is bound to upset him. He is certainly not a moral character, but he also has redeeming qualities. Much of the first four seasons are devoted to his moral ambiguity before he becomes more of a full-on hero in the later seasons. These are the five most despicable things The Hound ever did (and five times he was a hero).
Despicable: Killing Mycah
For those who don't remember, Mycah was a humble butcher's son who strikes up a friendship with Arya Stark. Unfortunately, their friendship is interrupted by the always unpleasant Joffrey Baratheon, who bullies Mycah and slashes his cheek.
When Nymeria defends them and bites Joffrey, Joffrey lies about the events and The Hound is sent to kill Mycah in retaliation. He takes pride in his work, telling Ned, "He ran. Not very fast."
Hero: Saving Loras Tyrell
The first hint we get of The Hound's heroism is when he saves Loras Tyrell from the might and brutality of The Mountain. When Loras unhorses Gregor during a joust, a frustrated Gregor looks to murder him with his sword - that is, until The Hound intervenes and stops him.
It takes a lot of guts to stand up to The Mountain That Walks, and The Hound has those guts. He is honored by Loras and cheered by the crowd for his heroic efforts.
Despicable: Massacre In The Red Keep
Upon Robert's death, Ned finally confronts Cersei about Joffrey's lineage and his right to the Throne. This proved to be a fatal mistake. The order is given to massacre Ned's men and take Ned prisoner.
Upon the order, Lannister soldiers, the City Watch, and The Hound himself attack Ned's men and spill a lot of blood in the Red Keep. The Hound was defending his King and following orders, but as we saw in the Battle of the Blackwater, The Hound doesn't always follow orders.
Hero: Trying To Rescue Sansa
By the end of season two, The Hound is left feeling protective of Sansa, who he has taken to calling Little Bird.
During the Battle of the Blackwater, The Hound ignores orders and deserts his post owing to his fear of the wildfire. While escaping the city, he meets Sansa and tells her that he can get her out of the city and take her back to Winterfell. Unfortunately, Sansa declines his offer, believing that she will be safe in the hands of Stannis.
Despicable: Showing Off Ned's Head
Following orders and slaughtering Ned's men is one thing, but proudly showing off his decapitated head is quite another.
Immediately following Ned's execution, Sandor picks up the decapitated head and proudly shows it off to the adoring and bloodthirsty crowd. It's borderline barbaric, and it's made even worse due to Sansa's immediate presence.
Hero: Rescuing Arya
While he fails in his attempt to rescue Sansa, he is successful in saving her younger sister, Arya. He takes Arya after she flees from the Brotherhood and plans to ransom her to her family in Riverrun.
Unfortunately, the Red Wedding happens, and those plans are instantly thwarted. And when Arya attempts to run inside the castle to almost certain death, The Hound knocks her out and takes her away to safety.
Despicable: "Give Him What He Wants."
By the end of season one, Sansa is in such a tortured and grieving state that she plans to throw Joffrey off the battlements.
This is noticed by The Hound, who stops Sansa before she has a chance to reach Joffrey. To spare Sansa from Joffrey's wrath, he gives Sansa a handkerchief to wipe her bloody lip. Following that, he tells Sansa to "give [Joffrey] what he wants." This, after she was forced to look at her father's head on a spike. He says it to spare Sansa future pain, yes, but giving Joffrey whatever he wants is plenty painful enough.
Hero: Going Beyond The Wall
In season six, a still-alive Sandor meets up with the Brotherhood Without Banners, who are planning on going North to aid in the fight against the White Walkers.
Upon reaching Eastwatch, they are taken prisoner and recruited by Jon to head north of the Wall to collect a wight. They successfully do so, proving that the threat is very real and in need of immediate attention.
Despicable: Telling Cersei About Sansa
In the second season episode A Man Without Honor, Sansa has her first period. Unfortunately for her, this means that she can now bear Joffrey's children.
While she and Shae attempt to cover up the evidence in a desperate act of prolonged innocence, The Hound catches them in their attempt. Rather than keeping it a secret, he informs on them to Queen Cersei, and plans are swiftly put in motion for child rearing.
Hero: Saving Arya From A Life Of Violence
The final scene between The Hound and Arya is a touching one indeed. Arya is solely focused on murdering Cersei, but The Hound stops her in a desperate attempt to revert her back to the child she was.
He tells her that revenge isn't worth it, as it only leads to a life of misery and nihilism like The Hound's. He spares her from that future and saves her from certain death - both physical and spiritual.