The part that got me was when Harry was walking in the forest talking to his mom and dad, and asked them "You'll stay with me?" and his dad replied, "until the very end."
That part threw me for a loop, because I pretty much thought Harry was going to take a ride on the Afterlife Express at that point.

I thought Kreacher's conversion from spiteful (yet hilarious) pain in the ass to helpful defender to be quite fast, especially considering the size of the book. But he was a cute character. I wish she'd have had him mumbling under his breath some more.