Remus Lupin was supposed to be on the H.I.V. metaphor. It was someone who had been infected young, who suffered stigma, who had a fear of infecting others, who was terrified he would pass on his condition to his son. And it was a way of examining prejudice, unwarranted prejudice towards a group of people. And also, examining why people might become embittered when they're treated that unfairly.

But Death was cunning.

You are determined to hate him [Snape], Harry,” said Lupin with a faint smile. “And I understand; with James as your father, with Sirius as your godfather, you have inherited an old prejudice. By all means tell Dumbledore what you have told Arthur and me, but do not expect him to share your view of the matter; do not even expect him to be surprised by what you tell him. It might have been on Dumbledore’s orders that Severus questioned Draco.

And his knowledge remained woefully incomplete, Harry! That which Voldemort does not value, he takes no trouble to comprehend. Of house-elves and children's tales, of love, loyalty, and innocence, Voldemort knows and understands nothing. Nothing. That they all have a power beyond his own, a power beyond the reach of any magic, is a truth he has never grasped.

We all know that the people we love are mortal, we all know we’re mortal, we know it’s going to end; you cannot prepare yourself for it.

I thought it sounded a bit like Percy singing... maybe you've got to attack him while he's in the shower, Harry.

My Head of House said I lacked certain necessary qualities...like the ability to behave myself.