He had never had a proper conversation with the headmaster outside of Hogwarts before; there was usually a desk between them. (4.1)
Harry and Dumbledore's friendship changes and deepens throughout the course of Harry Potter and the Half-Blood Prince. They become more like colleagues, equals. Dumbledore trusts Harry enough to let him in on all of the details of his top-secret quest to find Voldemort's Horcruxes. The two trust each other implicitly.
"Or perhaps, to confess that you yourself are worried and frightened? You need your friends, Harry. As you so rightly said, Sirius would not have wanted you to shut yourself away." (4.212)
Dumbledore knows that friendship is the key to life; we cannot exist without good friends to help us and to love us. Harry cannot carry the prophecy by himself – it would be too much of a burden. Dumbledore knows this and knows that all humans need support. Harry, Ron, and Hermione's friendship is pretty rare and deep. Voldemort does not have any friends, making him extremely different from Harry.
"A warmth was spreading through him that had nothing to do with the sunlight; a tight obstruction in his chest seemed to be dissolving. He knew that Ron and Hermione were more shocked than they were letting on, but the mere fact that they were still there on either side of him, speaking bracing words of comfort, not shrinking from him as though he were contaminated or dangerous, was worth more than he could ever tell them." (5.203)
If Harry is "pure of heart," than we argue that Ron and Hermione are too. They do not hang out with Harry in the hopes of finding great wealth, fame, and fortune. They do not always agree with Harry or support what he does. They are friends with Harry because they like him as a person, they have similar likes and dislikes, and they have fun together. Harry never once seeks out friends that will make him seem cool or popular or edgy. He stays true to himself, and, as a result, we get a glimpse of one of the greatest friendships in all of literature.
"Hi, Harry, I'm Romilda Vane," she said loudly and confidently. "Why don't you join us in our compartment? You don't have to sit with them," she added in a strange whisper, indicating Neville's bottom which was sticking out from under the seat again as he groped around for Trevor, and Luna, who was now wearing her free Spectrespecs, which gave her the look of a demented multicolored owl.
"They're friends of mine," said Harry coldly. (7.103-104)
Hogwarts is not immune to the petty drama and to the silly cliques that we experience all the time in school. We've seen Gossip Girl. There's something about the process of growing up that makes people terrified of being left out or of being considered "uncool." It's kind of comforting to know that even wizards and witches struggle with their own sense of coolness and sense of self sometimes.
It was a mark of the strength of their friendship that Ron did not laugh. (8.116)
Ron doesn't laugh at the fact that Malfoy froze Harry and then broke his nose with his foot. At the time of the attack, this seemed like a pretty violent thing for Malfoy to do, and we were really worried for Harry. But, at the same time, it was kind of silly of Harry to wrap himself in his invisibility blanket just to sit in the luggage rack of the Slytherin compartment on the Hogwarts Express – his foolishness in this regard is a bit laughable. And yet, we've got to hand it to Harry for being in it to win it. He's willing to try anything in order to get the right information. Ron must recognize that too at this moment.
Exactly what Hagrid would say when he realized his three favorite students had given up his subject, he did not like to think. (8.137)
Do you agree with the way Harry, Hermione, and Ron deal with Hagrid at the beginning of Harry Potter and the Half-Blood Prince? Are they being good friends to Hagrid? What could they have done to be a better friend to him? What is the nature of the three's friendship with Hagrid: how long have they been friends, what have they experienced together, how have they helped each other?
"Lord Voldemort has never had a friend, nor do I believe that he has ever wanted one." (13.188)
Again, we see here a big difference between Voldemort and Harry. Voldemort wants to separate himself from the people around him, while Harry's friendships are the thing that sustains him. If Voldemort had had a friend at one point in his life, what kind of friend would it have had to have been?
He and Cho were now too embarrassed to look at each other, let alone talk to each other; what if Ron and Hermione started going out together, then split up? Could their friendship survive it? Harry remembered the few weeks when they had not been talking to each other in the third year; he had not enjoyed trying to bridge the distance between them. And then, what if they split up? What if they became like Bill and Fleur, and it became excruciatingly embarrassing to be in their presence, so that he was shut out for good? (14.33)
Ruh roh. Love is getting in the way of friendship, or at least that's at the top of Harry's worry list right after "Defeat Lord Voldemort" and "Figure out what Draco is cooking up." Ron and Hermione don't get together in this story, but does that preserve the dynamic between the triumvirate (Harry, Ron, and Hermione)? How does love affect their relationships? And, what has happened between Harry and Cho?
"Nobody's ever asked me to a party before, as a friend!" (15.72)
Oh Luna, once again, you rule. There's something totally charming and winning about the fact that Harry dodges the love darts aimed at him by the likes of Romilda Vane by asking out a girl who is not considered to be the coolest kid on the block. Luna's earnest glee at being able to go to a party in this moment is infectious. Did anyone notice that a Slughorn party is kind of like a mini prom or a Blair Waldorf party (Gossip Girl, anyone)? It's all about who you are with and what you wear, and not everyone gets invited.
[Harry:] "He accused me of being 'Dumbledore's man through and through.'"
[Dumbledore:] "How very rude of him."
[Harry:] "I told him I was."
Dumbledore opened his mouth to speak and then closed it again. Behind Harry, Fawkes the phoenix let out a low, soft, musical cry. To Harry's intense embarrassment, he suddenly realized that Dumbledore's bright blue eyes looked rather watery, and stared hastily at his own knees. When Dumbledore spoke, however, his voice was quite steady. (17.83-86)
Harry expresses his ultimate loyalty and devotion to Dumbledore in this moment. We are moved by just how moved Dumbledore is. He is the greatest wizard around, and yet he's not without an understanding of how rare and valuable true friendship and loyalty are. We imagine him to be quite an impressive sight in all of his bearded glory and star-flecked robes. But to see him cry makes us wonder whether Dumbledore has many friends. Does his job make it impossible for him to have friendships with others?
"Ah, Harry, how often this happens, even between the best of friends! Each of us believes that what he has to say is much more important than anything the other might have to contribute." (17.104)
As much as we want to believe that Harry and Dumbledore have a friendship that is unshakeable and unflappable, it gets severely rattled in Harry Potter and the Half-Blood Prince, and all because of Snape. At first, we do think that Harry is being a bit pushy with Dumbledore, and we assume that Dumbledore must know something that Harry doesn't know about Snape and Draco. He is the greatest wizard in the world, after all. In retrospect, it is strange and eerie to think that Dumbledore would not listen to Harry's warnings and suspicions, that he even asserted his authority over Harry in order to squelch them. Had he listened to Harry, he might not have died.