Several lines from Changes, including most of Harry's conversation with Uriel (in a weird way) but especially, "Whatever you do, do it for love. If you keep to that, your path will never wander so far from the light that you can never return," Especially when you realize he is preparing Harry to become the Winter Knight. and a few lines from the end, when Ebenezar says "Oh, Hoss," and when Leanansidhe promises to see to Susan's body Harry comments, "A direct promise from one of the Sidhe is a rare thing. A kindness is even rarer. But I guess I shouldn't have been surprised: Even in Winter, the cold isn't always bitter, and not every day is cruel."
Lea's bit, while small, is significant because it comes right after Harry kills Susan. This act of kindness, from a being who is usually anything but, demonstrates that life and love go on. It's stunningly effective simply because it's Lea; it wouldn't have worked half as well from, say, Ebenezar, because it's just what we expect from him. We don't expect it from the crazy death Sidhe lady.
A crazy death Sidhe lady who genuinely loves Harry - in her own weird Faery way - and probably loved his mother too.
And one who'd probably come to respect Susan herself more than she does most mortals, by then.
Harry's apartment is connected to her garden in the Nevernever. She admits to having watched over him in his sleep and destroyed anything that would harm him from the other realm for the past several years.
Also from Changes, Harry's conversation with Molly—she has always known that Daddy would ShowUp when she needed him. But because of the events of Small Favor, although he's still there, Michael isn't combat-capable anymore.
Harry: "Tell you what,grasshopper. You ever need rescuing, I'll handle that."
He tells her that Michael will still be her father. He will always take care of her, fix anything that needs fixing, visit her with ice cream after a bad break up...just because he can't fight anymore, doesn't mean he can't Show Up for her when she needs a dad. Doubles as Tearjerker when Harry notes that most people take that for granted.
When we get to hear Mouse talk thanks to Lea, and he tells her that Harry didn't 'win him' it was the other way around, Mouse won Harry.
The moment where everyone picks what Lord of the Rings characters they are. Despite Harry being miffed at not getting to be Gandalf, during a conversation with Uriel later in the book, the Archangel tells him who everyone actually thought he should be, and everyone who's read the books and seen the movies knows how important this is: To everyone else, Harry isn't Gandalf. He's Sam.
From Maggie's perspective, the whole book. Mama Bear and Papa Wolf lay waste to an entire nation of gruesome supernatural monsters and sacrifice all that they are and have to get her back and keep her safe. THAT is what being a parent is all about, ladies and gentlemen.