The image of Hagrid reading Harry's letters aloud is so true to that character; it's going to stay with me for a long while.
But really, it's Harry and Severus here. I blinked for a moment when Severus brought out his ultimate Slytherin to get Harry to drop his guards, but I never quite forgot that he was a Slytherin.
Oh and Harry's cock fetish; Severus, of course, having the most perfect one ever.
Just a wonderful story that I'll enjoy more than once, I'm sure.