Dumbledore: It takes a great deal of bravery to stand up to your enemies, but a great deal more to stand up to your friends.
Hermione Granger: I'm going to bed, before either of you come up with another clever idea to get us killed, or worse, expelled.
Ronald Weasley: [to Harry.] She needs to sort out her priorities.
Draco Malfoy: Think my name's funny, do you? No need to ask yours. Red hair... And a hand-me-down robe. You must be a Weasley.
Albus Dumbledore: Ah, Bertie Bott's Every Flavor Beans. I was most unfortunate in my youth to come across a vomit flavoured one. I must say since then I have lost my liking for them. But I think... I might be safe... with a nice toffee. [He has a bean.] Alas. Earwax.
Minerva McGonagall: Do you think it is wise to trust Hagrid with something as important as this?
Albus Dumbledore: Ah, Professor, I would trust Hagrid with my life.
Dumbledore: Also, our caretaker, Mr. Filch, has asked me to remind you that the third-floor corridor on the right-hand side is out of bounds to everyone who does not wish to die a most painful death.
Dumbledore: Only a person who wanted to find the Stone - find it, but not use it - would be able to get it. That is one of my more brilliant ideas. And between you and me, that is saying something.
Ron: I think we've had a bad influence on her.
Caretaker Argus Filch: A pity they let the old punishments die. Was a time detention would find you hanging by your thumbs in the dungeons. God, I miss the screaming.
Draco Malfoy: It's true then, what they're saying on the train. Harry Potter has come to Hogwarts.
Seamus Finnigan: I'm half and half. Me dad's a muggle; Mam's a witch. Bit of a nasty shock for him when he found out.
Percy Weasley: And keep an eye on the staircases. They like to change.
Harry: I swear I don't know. One minute the glass was there and then it was gone. It was like magic.
Uncle Vernon: There's no such thing as magic!
Olivander: Curious...
Harry Potter: I'm sorry, but what's curious?
Olivander: I remember every wand I've ever sold, Mr.Potter. Every single one. It's curious that you should be destined for this wand, when its brother gave you that scar.
Ron: Mental that one, I'm telling you.
Chosen answer: There are several reasons. First, the position is cursed, so there is little reason to give Snape the job when he will not last any longer than all the previous instructors. If Snape did become the DADA instructor, something could happen to him that could result in his being harmed, having to leave Hogwarts, or be otherwise incapacitated in some way; that would render him useless to Dumbledore as a double agent. Also, Dumbledore trusts Snape, but putting him in an environment where he is teaching about dark magic on a daily basis would be too tempting and emotionally compromising to someone who had been so easily seduced by the dark side. He could possibly relapse. It would be like having a recovering alcoholic work as a bartender. Of course, he does eventually become the DADA instructor, and lasted no longer than his predecessors.
raywest ★
In the movies it is never mentioned that DADA role was cursed by Voldemort.
This is true; though it doesn't say it's not either. With trying to fit 7 long books and years worth of pages of HP information in 2 and a half hours; as long as the movie doesn't say it's not cursed, with our knowledge, there is no problem with reporting that it is. Even directors of non-book movies do this all the time; leave background information out that helps explain things they just didn't have time so they explained it behind the scenes.