You have to kill a lot of trees before you write anything good.

You can exist without your soul, you know, as long as your brain and heart are still working. But you’ll have no sense of self anymore, no memory, no . . . anything. There’s no chance at all of recovery. You’ll just — exist. As an empty shell. And your soul is gone forever . . . lost.

I don't think you should be an Auror, Harry," said Luna unexpectedly. Everybody looked at her. "The Aurors are part of the Rotfang Conspiracy, I thought everyone knew that. They're working to bring down the Ministry of Magic from within using a mixture of dark magic and gum disease.

there is plenty to be learned even from a bad teacher: what not to do, how not to be

They don’t need walls and water to keep the prisoners in, not when they’re trapped inside their own heads, incapable of a single cheerful thought. Most go mad within weeks - Lupin

Are — you — insane?” said Hermione in a hushed voice. 'I don't think so,' said Harry, shrugging.

The knowledge that you have emerged wiser and stronger from setbacks means that you are, ever after, secure in your ability to survive.