Harry Potter and the Order of the Phoenix
How we cite our quotes:
"[Harry's]'s not your son," said Sirius quietly.
"He's as good as," said Mrs. Weasley fiercely. "Who else has he got?"
"He's got me!"
"Yes," said Mrs. Weasley, her lip curling, "the thing is, it's been rather difficult for you to look after him while you've been locked up in Azkaban, hasn't it?" (5.124-127)
So, Mrs. Weasley definitely goes too far with this one: it's not Sirius's fault that Peter Pettigrew framed him for murder, leaving him stuck in Azkaban prison for twelve years. At the same time, this is an example of the kinds of goads that contribute to Sirius's later recklessness at the end of the novel. Harry blames Professor Snape for Sirius's poor state of mind, but it's not just him – Mrs. Weasley, Fred, and George all goad Sirius at one time or another for his lack of participation in the war and Harry's upbringing. By the time Harry heads to the Department of Mysteries, everyone in Sirius's life has made him good and ready to risk everything, no matter what the consequences – he just can't stand to be trapped any longer.
"If my parents could see the use their house was being put to now ... well, my mother's portrait should give you some idea ..."
[Sirius] scowled for a moment, then sighed.
"I wouldn't mind if I could just get out occasionally and do something useful. I've asked Dumbledore whether I can escort you to your hearing – as Snuffles, obviously – so I can give you a bit of moral support, what d'you think?" (6.187-189)
Dumbledore claims, at the end of Book 5, that he just wanted to keep Sirius safe by locking him away at Number Twelve, Grimmauld Place. But Dumbledore seems to have no respect for psychology: would you call Sirius's current state of mind, when he's so desperate to leave the house that he just wants to turn into a dog and escort Harry to the train station, safe? Keeping Sirius locked up for a year is essentially asking for trouble – what was Dumbledore thinking?
"You belong at Hogwarts and Sirius knows it. Personally, I think he's being selfish. [...] He'll have company!" said Hermione. "It's Headquarters to the Order of the Phoenix, isn't it? He just got his hopes up that Harry would be coming to live here with him."
"I don't think that's true," said Harry, wringing out his cloth. "He wouldn't give me a straight answer when I asked him if I could."
"He just didn't want to get his own hopes up even more," said Hermione wisely. "And he probably felt a bit guilty himself, because I think a part of him was really hoping you'd be expelled. Then you'd both be outcasts together." (9.62-66)
First off, Hermione is fifteen just like Ron and Harry. We know that she's brilliant, but how exactly did she get so wise about the motivations of other people? Sometimes, she does seem almost too brilliant. But anyway, we agree with her assessment of Sirius here: Sirius knows intellectually that it's better for Harry to go back to Hogwarts, but he wishes emotionally that Harry would be expelled so that he could have a friend at Number Twelve, Grimmauld Place. The problem with the relationship between Harry and Sirius is that Harry is looking for a father in Sirius, while Sirius is looking for a friend (and not so much a son, for whom he would have to be responsible) in Harry. They can't really give each other what they want, so their relationship is probably doomed to tragedy from the start.