Albus Dumbledore went from perhaps the most mysterious character of the Harry Potter franchise to someone fans know almost everything about. The series revealed more and more about this character, as well as J.K. Rowling dropping post-canon facts about the man (that aren't always met with fan approval), and a series of spin-off movies where he features as a prominent character.
He's still controversial though, and has had many mixed moments throughout the series. Sometimes, fans have been made to feel extremely bad for the most powerful wizard in the series. Others, they've truly hated him for some misguided choices.
Felt Bad: When Harry Smashed Up His Office
At the end of Order of the Phoenix, Harry has just gone through an ordeal. He watches his godfather die because of Dumbledore's bad choices and although he doesn't really blame Dumbledore, he needs to vent his anger and ends up destroying the heaster's office. Dumbledore doesn't even attempt to stop him — he just watches with tears in his eyes, and it's obvious there's real guilt there.
Hated Him: Leaving Harry With The Dursleys
Dumbledore has his reasons for leaving Harry with the Dursleys. He talks about the fact that only family can protect Harry, but fans didn't really buy it since Hogwarts could apparently protect him for the rest of the year.
Regardless, he leaves Harry in the hands of his abusive aunt and uncle, and he suffers pretty greatly for ten years. It's a choice that Dumbledore found it impossible to justify to his critics, and even to readers of the books who didn't agree with him.
Felt Bad: His Death
It's impossible not to feel bad for Dumbledore when he dies, especially not knowing the context. He pleads with Severus and is murdered, falling from the tower as he dies. It's difficult to see such a powerful wizard go down, and it really heralds the end of any innocence Harry has left. How is it possible not to feel bad?
Hated Him: Defending Snape
There are so many times when Dumbledore justifies his decision to keep Snape around as a teacher. Yes, it turns out Snape was instrumental in the fight against Voldemort — but that doesn't erase the fact that he's an abusive teacher. He constantly talks down to students, going as far as to bully Hermione for her appearance when she's only in her fourth year. This is pretty inexcusable, and Dumbledore should be harsher in his disciplinary action.
Felt Bad: When Voldemort Returned
In Goblet of Fire, Dumbledore finds out Voldemort has returned when Harry slams into the ground with a portkey, clutching Cedric Diggory's body, and later explains to Dumbledore what happened in the graveyard.
Dumbledore is described as looking old and weary, and it's a reminder that although he's a powerful wizard, he's also an old man who's suffered a lot.
Hated Him: Ignoring Harry
In Order of the Phoenix, Harry feels Lord Voldemort start to force his way into his mind and rather than try to help him, Dumbledore ends up distancing himself so Voldemort can't use Harry to spy on him. For most of the book and movie, readers aren't aware of this. Harry is just aware that Dumbledore has seemingly abandoned him in his time of need.
Felt Bad: When The Ministry Tried To Arrest Him
In Chamber of Secrets, Cornelius Fudge tries to arrest Dumbledore in a misguided attempt to be seen doing something when a monster has been let loose in the school.
Dumbledore has tried so hard to protect the students and keep Hogwarts a safe place, and to receive no credit from the Ministry is pretty awful. It's a sign that although he's widely revered, he doesn't always get the respect he deserves.
Hated Him: Letting Harry Participate In The Triwizard Tournament
When Harry's name emerged from the goblet of fire, Dumbledore letting him participate wasn't a popular choice. Even Snape looked at him oddly, and Professor Minerva McGonagall was downright appalled by the decision. There's no justification given for this even later — why not protect Harry, by withdrawing him from the competition? He's only fourteen, not skilled enough to compete (although he manages), and is in serious danger since the rumors of Voldemort growing stronger are floating heavily around the school.
Dumbledore doesn't always make choices with a clear reason behind them, but this one is beyond understanding.
Felt Bad For Him: Learning About His Past
Readers and viewers initially learn about Dumbledore's past properly in Deathly Hallows, and it's pretty harrowing. He was friends with Grindelwald (in love with, but Rowling didn't include that in actual printed canon), and his sister died in a duel between them when thinks went south. As a result, he's highly aware of how easily he's drawn in by power and spends his days lonely and trying to keep himself from regressing into someone who doesn't always have the best intentions.
It makes him multi-layered, and a little easier to relate to.
