Hermione says something very important in chapter 32 of Order of the Phoenix, something which helps define the overarching plot of the entire seven-book series.

When Harry is frantically describing the vision he had of Sirius captured and tortured by Voldemort in the Department of Mysteries, Hermione tries to reason with him.

‘OK,’ she said, looking frightened yet determined, ‘I’ve just got to say this -‘

‘What?’

‘You… this isn’t a criticism, Harry! But you do… sort of… I mean – don’t you think you’ve got a bit of a – a – saving-people thing!’ she said.

He glared at her.

‘And what’s that supposed to mean, a “saving-people thing”?’ (OP32)

It’s true. Harry does have a “saving-people thing.” It’s an integral part of who he is, how he views his place in the world. This aspect of his nature has been developing over almost five years of time at Hogwarts. He risked his life to save Hermione in book one when the troll was loose in the school. In the second book he again risked his life to enter the Chamber of Secrets and save Ginny’s life. Sirius and Buckbeak were the recipients of his selfless “saving-people thing” in book three. And, as Hermione points out, he went above and beyond to save Gabrielle Delacour in book four.

Harry has developed a sense that it’s all up to him. He’s also discovered that selflessly charging in and using his nascent skills to fight against the enemy, be it a basilisk or a hoard of dementors, wins the day. His “saving-people thing” works.

But Hermione senses something else, something dangerous about this heroic streak. She knows that all of Harry’s daring and skill isn’t nearly powerful enough to battle the truly legendary power of a wizard like Voldemort. She knows that charging in and fighting can also be a death sentence. And as Harry himself pointed out in the Hog’s Head, his successes have been due as much to luck and the help of others as to his own prowess. As he says, “I don’t want to sound like I’m trying to be modest or anything, but… I had a lot of help with all that stuff…”

So yes, he has a “saving-people thing,” and yes, he’s trying to enlist help again now to go rescue Sirius. Hermione is understandably cautious, knowing that the rescue mission Harry is proposing might be a bit more than they can handle. So she asks him to think about things logically before letting his “saving-people thing” kick in.

But Hermione’s statement is actually more profound than even she realizes. What becomes obvious over the next few hours is that Harry’s “saving-people thing” is not only a strength. It’s also a weakness which Voldemort is exploiting. And the hubris that goes along with it is perhaps the most dangerous aspect of all. Harry is starting to believe that he’s the hero who can defeat Voldemort. Harry sees himself as becoming what I call “Superhero Harry.” He’s competed with the older students in the Triwizard Tournament and outflown a dragon. He’s driven off a hoard of Dementors. He’s killed a basilisk. He’s a Quidditch hero. And if that weren’t enough, he is also the son of the revered James Potter.