At the beginning of the novel, much of Harry's anger stems from his belief that Ron, Hermione, and Sirius are all closely involved with the exciting and meaningful resistance effort against Voldemort, while he sits, alone and ignored, in his bedroom at the Dursleys' house. However, once Harry travels to number 12, Grimmauld Place--the headquarters of the resistance group the Order of the Phoenix--Harry discovers that resistance is nowhere near as exciting or interesting as he thought it would be, and not just because its members keep most of the Order's information secret from him. With this experience, Harry begins to consider the possibility that resistance efforts are as much, if not more, about feeding people, performing domestic labor, and completing basic spell work as they are about fighting enemies in direct and exciting ways.
Harry's arrival at number 12, Grimmauld Place impresses upon him that living at the headquarters of the resistance doesn't mean that anyone, adults and children alike, is particularly thrilled with the form that the resistance takes. He discovers that his suspicions that Hermione and Ron were keeping things from him and not telling the whole truth in their letters were wrong: Hermione and Ron know very little about the Order and couldn't have told him anything exciting, even if they'd been allowed to.
Instead of learning what the Order is planning, Hermione, Ron, Harry, and the other Weasley children instead spend most of their time cleaning number 12 and "making it fit for habitation," as the house--Sirius's childhood home--has been empty since Sirius's mother died twelve years ago. Mrs. Weasley in particular insists that this is an essential part of the Order's efforts and an effective way to help the Order, which introduces Harry to the idea that resistance and war don't look or feel as showy as he, in his youth, thinks they should. Instead, resistance at this point means creating a safe and comfortable space where the Order can work on its plans and concentrate on fighting Voldemort, rather than fearing that the house itself (which is infested with all manner of nefarious pests and spells) will turn on them. It's also important to note that Mrs. Weasley, who appears to be one of the most important members of the Order, is celebrated by Order members primarily for her cooking. During the time in which Harry and his friends are at Grimmauld Place, Mrs. Weasley can most often be seen cooking or providing food to Order members or the children. Though Harry might not realize it or accept it, the sheer amount of domestic labor that Mrs. Weasley and Sirius perform at Grimmauld Place illustrates clearly that resistance efforts run on mundane, daily work, not on showy battles or campaigns.
Throughout the novel, Harry discovers that even in the case of actual action--not just the labor that enables that action--the action itself is often boring, even for the adults performing it. For example, Mr. Weasley falls asleep while he's guarding the "weapon" that Voldemort is after one night. Put another way, while Mr. Weasley may be fighting the good fight and performing a completely necessary task, that doesn't mean that the task itself isn't boring and tedious enough to put him to sleep.
The way that Harry talks about the "weapon" itself also shows Harry's youth and misconceptions about what resistance efforts are like. The fact that Harry decides that the Order must be guarding a weapon of some sort betrays Harry's desire for fighting Voldemort to be exciting and violent, not a matter of controlling and protecting information--which is exactly what the Order turns out to be doing. The Order is guarding the prophecy that foretold Harry's birth and the fact that Voldemort would turn Harry into his worst enemy, information that Voldemort believes will help him gain power. It’s telling that what Voldemort wants is information and information only, something that on paper and in conversation is far less compelling than weapons, dangerous spells, or powerful magical objects.
While this is all incredibly disheartening and frustrating for Harry, the way in which he organizes his lessons for Dumbledore's Army, his secret Defense Against the Dark Arts student organization, shows that he has internalized the idea that resistance is built on basics and on the acquisition of information, not on extravagant heroism. The entire first term of Harry's lessons focuses on teaching the members of the D.A. useful yet simple spells, such as Disarming or Stunning spells. While not particularly exciting or difficult, Harry recognizes that having these basics is essential to being able to understand and perform the more advanced magic that he teaches in the spring, such as the Patronus Charm. Further, he's open with the members of the D.A. that these simple spells have been the ones he's used against Voldemort and that have allowed him to live to tell the tale. Indeed, when Harry and a few members of the D.A. do face Voldemort's Death Eaters, the spells they use are exclusively the basic yet highly effective ones that Harry drilled them on in the fall. While the group does come away with a few injuries, they also all walk away from the experience alive--which speaks to the power and the efficacy of these basics in the face of exciting and dangerous confrontations.
As a whole, Order of the Phoenix makes the case that in order to be successful in these dangerous confrontations when they do arise, it's necessary to first do the boring work of acquiring a firm grasp of basics, understanding the power of information, and respecting the necessity of making sure people involved in a resistance effort have food, shelter, and a sense of safety as they carry out their work.
War: Excitement vs. The Mundane ThemeTracker
War: Excitement vs. The Mundane Quotes in Harry Potter and the Order of the Phoenix
"So, got there yet?" said George eagerly.
"The weapon Sirius mentioned?" said Harry.
"Let slip, more like," said Fred with relish, now sitting next to Ron. "We didn't hear about that on the old Extendables, did we?"
"What d'you reckon it is?" said Harry.
"Could be anything," said Fred.
"But there can't be anything worse than the Avada Kedavra curse, can there?" said Ron. "What's worse than death?"
The fact was that living at the headquarters of the anti-Voldemort movement was not nearly as interesting or exciting as Harry would have expected before he experienced it. Though members of the Order of the Phoenix came and went regularly, sometimes staying for meals, sometimes only for a few minutes' whispered conversation, Mrs. Weasley made sure that Harry and the others were kept well out of earshot (whether Extendable or normal) and nobody, not even Sirius, seemed to feel that Harry needed to know anything more than he had heard on the night of his arrival.
He and the D.A. were resisting under her very nose, doing the very thing that she and the Ministry most feared, and whenever he was supposed to be reading Wilbert Slinkhard's book during her lessons he dwelled instead on satisfying memories of their most recent meetings, remembering how Neville had successfully disarmed Hermione, how Colin Creevy had mastered the Impediment Jinx after three meetings' hard effort, how Parvati Patil had produced such a good Reductor Curse that she had reduced the table carrying all the Sneakoscopes to dust.
"Bitten by a werewolf, poor chap. No cure at all."
"A werewolf?" whispered Mrs. Weasley, looking alarmed. "Is he safe in a public ward? Shouldn't he be in a private room?"
"It's two weeks till full moon," Mr. Weasley reminded her quietly.
"I'm trying to say—Voldemort knows you, Harry! He took Ginny down into the Chamber of Secrets to lure you there, it's the kind of thing he does, he knows you're the—the sort of person who'd go to Sirius's aid! What if he's just trying to get you into the Department of Myst—"
"Like the fact that the person Sirius cared most about in the world was you," said Dumbledore quietly. "Like the fact that you were coming to regard Sirius as a mixture of father and brother. Voldemort knew already, of course, that Sirius was in the Order, that you knew where he was—but Kreacher's information made him realize that the one person whom you would go to any lengths to rescue was Sirius Black."
"I cared about you too much," said Dumbledore simply. "I cared more for your happiness than your knowing the truth, more for your peace of mind than my plan, more for your life than the lives that might be lost if the plan failed. In other words, I acted exactly as Voldemort expects we fools who love to act."