Hermione slapping Draco in the face. Little twerp had it coming...
And then driving Draco (who, remember, never hesitates to toss a taunt or racial slur her way) into full retreat by merely pulling out her wand. It suddenly occurred to him that he's just pushed the most talented witch in the school one inch too far.
Ron has had his leg broken by a deranged murderer (he is led to believe) and can basically be defeated by a stiff wind. So he tells that same murderer, if he wants Harry, he'll have to go through him.Steve Kloves can be safely ignored on this front: Ron is Harry's man, through and through.
An easily missed example of this is when the Grim, really Sirius,attacks Harry, Ron, and Hermione to get at Pettigrew. Out of the three, Ron has been the most superstitious about the Grim throughout the whole book. So what does he do when he sees a massive dog that looks like a Grim attack Harry? He instantly gets to his feet and pushes Harry out of the way, letting the Grim take him instead.
Expecto Patronum! A lone 13-year-old boy against more than a hundred soul suckers. The boy wins.
The Quidditch Final.
The entirety of the Shrieking Shack scene.
"The Marauder's Map never lies. Peter's alive, Harry. Ron's holding him."
"I want to finally commit the murder I was imprisoned for!"
"If you want to get to Harry, you'll have to go through me!"
"THEN YOU SHOULD HAVE DIED! DIED RATHER THAN BETRAY YOUR FRIENDS, AS WE WOULD HAVE DONE FOR YOU!"
Boy scoutsthey weren't, but the Marauders - a bunch of teenagers not much older than Harry and his friends were at the time of this book - not only learned the highly advanced process of becoming Animagi (for the sake of a friend, but also created a detailed map of the near entirety of Hogwarts Castle that is also capable of tracking the location of any student that sets foot there. It's stated to work well enough that Harry can use it nearly twenty years after its creation... and implied to still work just as well after nearly another quarter-century, at which point Word of God says Harry's son (fittingly named for two of the Marauders) takes the map for himself. The fact that they innovated such a powerful magical artifact at probably around 14 years old speaks to some immense talent.
Hermione punching Draco.
Snape gets one he never got in the books. Runs out of the Whomping Willow, sees a werewolf about to eat them, and his first response is to stand between the kids and the wolf. Not bad, Snape.