What Harry Potter (and the Half-Blood Prince) taught me:

1. "The problem is, Prime Minister, the other side has magic too," and due to pesky moral problems, their spells tend to be painful or lethal while ours knock them out for about five minutes

2. Chapter 2 is the best chapter in the entire series…'Well Azkaban was a nice gesture and all, Bellatrix, but not very useful.' And he's got Wormtail fetching drinks, cleaning the house and living behind a bookshelf. Omg is Snape the best character or what?

3. Narcissa is either very super sneaky and willing to endanger a friend in order to save her son…or she's pretty dumb and willing to endanger a friend and risk the Dark Lord's wrath turning on all three of them

4. It's a very very very good thing that Bellatrix never had any children. Especially sons.

5. If you find yourself in possession of the most loathsome House Elf in existence who just caused your godfather's death and the injury of a lot of friends, here is the first command you give: Kreacher, I order you to stop breathing

6. If you're trying to avoid someone, stage a fight and turn into a sofa rather than apparating away. It's much more effective

7. Slughorn is kind of hilarious and very entertaining. He collects people

8. Ginny can be very petty when blond Veelas are involved

9. What is the point of a super high security vault run by goblins if your friend's eldest brother can stroll in and take money out for you?

10. Harry is such a noob. Seriously. Inviting Narcissa Malfoy to get a couple of Death Eater pals to do them in. Why would you even go talk to her?

11. Hermione + Borgin and Burke's = Hilarious

12. It took six years, but Draco finally did something vaguely villain-y and didn't use the words, "Wait till my father hears of this, then you'll be sorry." Well done, Draco

13. Harry's obsession with Draco (however right it turned out to be in the end) needs to stop. It's way past being creepy.

14. Probably not the best idea to give away liquid luck to a sixteen year old, but Slughorn can do whatever he wants apparently

15. If you have a year left to impart some wisdom onto your favorite student who will have to fight the Dark Lord very soon, some pointers in dueling and the finer instructions of how to destroy a Horcrux should be discussed at some point

16. It shouldn't be a point of jealously that two friends were invited to spend an evening with Slughorn and other students. Enjoy your free night

17. When in doubt and with absolutely no proof, blame Draco

18. Tom Riddle was a super creepy child

19. Harry might have a little more cunning in him than I thought possible, although he would choose to show that talent in order to help a friend play better in a Quidditch match rather than something important

20. If you overhear a vague conversation in which no specific tasks or people are mentioned, assume that both Draco and Snape are Death Eaters

21. Who thought up Unbreakable Vows? Seems like the wizarding world is awfully cavalier about keeping those with magic alive. Quidditch in a lightning storm anyone?

22. Standing up for your morals is much more important than not pissing off the Minister of Magic (who used to be Head of the Auror Office)

23. Rather than discouraging Harry's unhealthy obsession with Draco and Snape, it is much more effective to hint vaguely that the situation is under control and to not worry about it

24. Slughorn is pretty useless. A Potions Master with no antidote on hand?

25. If you need to get a memory from someone who is obviously ashamed enough of it to change it, the direct and honest approach as to why you need the memory might work best rather than pussyfooting around forever

26. When reading about an unknown curse marked 'for enemies' it is best to try it out on a person first, rather than, say, I don't know, a tree. Or Kreacher.

27. If you happen to have a friend who successfully brewed Polyjuice potion as a second year, it might be smart to entice said friend into brewing some Felix Felicis

28. Harry kind of sucks at lying, but I give him an A for effort. It was Snape after all, and who really gets away with trying to lie to that guy

29. Defenses that are only triggered after the object they're protecting has been removed seem really stupid

30. It might be a little heartless, but a Silencing spell is not out of the question when your beloved Headmaster yells for you to kill him

31. Dumbledore is definitely a huge asshole. As if Harry wasn't already the most emotionally scarred sixteen year old in the history of the world, he deliberately keeps Harry in place, unable to move or speak, and forces him to watch one of the people he loves and is ridiculously loyal to be killed in front of him due to a fellow student and a teacher whom Dumbledore himself told him to trust

32. If there's a spell that creates a shield that only allows people with the Dark Mark to pass through, wouldn't it be a good idea to have a spell that doesn't let people with the Dark Mark pass. Then you'd only have to worry about that one guy…what's his name? Oh, Voldemort.

33. It's really sad that no one has any kind of doubts about Snape and why he killed Dumbledore. Think about it. McGonagall taught with him for years. Which also ties into #31. Dumbledore is a huge asshole because of what he did to Snape. If you want a Snape rant it will have to be it's own story because otherwise this will take forever.

34. Despite instructions to not tell anyone, it might be a smart move to inform someone, other than your two teenage friends, of the massive task which Dumbledore assigned to you. Just a thought, since you are the definition of unqualified and in over your head.

35. If your girlfriend is the youngest child and only daughter in a family of blood-traitors, there's a good chance that she's already in danger so you might as well have an enjoyable couple of months with her rather than breaking it off to be noble