* Arthur Weasley standing up to Dumbledore and telling him, no, Harry will not be taken back to the Dursleys, not under any circumstances.
* In chapter 33, Neville Longbottom standing up to his grandmother by sending her a Howler. Everybody within hearing range is shocked that anybody could send a Howler to Augusta Longbottom. And then one of the ladies realizes that the Howler is a result of [[OhCrap her own son's gossiping.]]
** Also, in the same chapter, Harry silencing Augusta's own Howler (the direct cause of Neville's Howler) and Neville's explaining to [=McGonagall=] his grandmother had sent it because Neville had "offended her bigoted, pure-blood sensibilities". And the group giving the gossiper the deserved punishment: even ''Hermione'' joined in, if only by teaching Harry a curse to make him look like an idiot.
** And about that punishment... Harry tried to assure [=McGonagall=] everything was under control, [[BlatantLies nobody would do anything]] and smile reassuringly, but the teacher was ''terrified''.
* In chapter 39, [[spoiler:Ron kills a Dementor, a feat that has never been done, with the Sword of Gryffindor, to save his and Hermione's souls. And then he taunts all of the other Dementors.]]
* Chapter 31: Harry [[spoiler: massacring an horde of Dementors with ''summoning charms''. OK, he had the Dementor-killing wards the Goblins had installed at the Burrow to do the killing part of the job, but still...]]
* Slughorn showing everyone the cunning of a ''real'' Slytherin, apparently listening his House's false complaints against Harry before using them to justify his actions to prevent ''them'' from bullying.