These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crack Pairing/Ships That Pass in the Night: Draco/Ginny and Sirius/Narcissa. The members of the former couple have only one bit of interaction in canon (second book, to be specific), and the members of the latter couple are never seen interacting in canon at all.
Crowning Moment of Funny - Upon seeing Harry naked, Draco says: "Well, would you look at that. Congratulations, Potter."
"I have been called many things in my life, Weasley, but never a vicious, cold-blooded piece of toast."
Draco in Leather Pants - Contrary to popular belief, Draco does not wear leather pants all throughout the story, he just poses in them during a famous scene in Draco Sinister.
Not so much poses in them as is forced to borrow a pair from Charlie Weasley. Draco had a badly-broken leg, and the mediwizards at the dragon camp with Charlie have to cut the old trousers away to get at the leg. Draco then borrows a pair of dragonhide trousers from Charlie (Charlie wears dragonhide leather, of course, to be as flame resistant as possible) and a trope is born.
Somewhat averted even as in a later chapter, Draco bemoans having ever donned the trousers to begin with and bitterly proclaims that he'll never wear such things again.
Some trope history: Cassandra Claire put Draco in leather pants due to an ongoing half-serious suggestion by horny readers. This is not the only instance of fanservice... the Harry/"Draco" kiss late in the series was to get the readers who constantly insisted Harry and Draco had hoyay in the trilogy, and/or begged Cassandra to give them some Harry/Draco slash to shut the fuck up already. Cassandra was very vocal about this, and came to openly resent her association with this trope, claiming it was mostly an inside joke between good friends, rather than a genuine plot device.
I Knew It - Cassie may well be the queen of this. She correctly predicted the name of Malfoy Manor, the positions Ginny and Ron would play on the Quidditch team, Fleur dating Bill, and possibly even Dumbledore's homosexuality. And, perhaps most impressively, that wizards are given watches on their seventeenth birthday.
Rooting for the Empire - Of a sort, since Draco is portrayed as an unlikable character in the actual Harry Potter books. However, since Voldemort and most of the other bad guys stay evil and Draco becomes sympathetic by having a Heel-Face Turn, it's not quite a straight example.