It happens a few times during Cold Days but the best is the first: Harry's reunion with Thomas. Thomas gets the drop on Harry when Harry tries to break into the Water Beetle to sail to Demonreach Island early on. Thomas delivers a heartfelt yet scathing speech regarding Harry's decision to have Kincaid take Harry out at the end of Changes. Once that's done, the very next thing he does is to hug his brother and hold on tight...while calling him every insult he can come up with. Thomas is every bit as bad ass as his brother.
Harry: What would it have changed? What could you possibly have said that would have made a difference?
Thomas: That was I was your brother, Harry. That I loved you. That I knew a few things about denying the dark parts of your nature. And that we would get through it. That we'd figure it out. That you weren't alone.
And then they hug, Supernatural-style, while Thomas rails off a list of insults at Harry and Harry responds with: "Yeah, I missed you too."
Just the fact that Thomas, the White Court vampire who's known real love from, at most, three other people in his life (Inari, Margaret Dresden and Justine), so readily says he loves his brother.
Actually, all the brotherly moments between Harry and Thomas in the book. Made even better when you realize why they're going at it even more with the banter and the teasing and the hugs - they really missed each other, and they're making up for lost time. It's pretty sweet to see how far they've come from when they couldn't have a proper conversation because of a 'guy thing'.
Mouse almost knocking down the door when he realizes Harry is alive and standing outside.
And then running in circles like an overjoyed puppy, wagging his tail so hard his hips rock back and forth.
Near the end of the book, Harry calls out Mab for everything she's done, everything she's put him through, and most specifically for turning Molly into the new Winter Lady. When Mab notes that she's killed for far lesser insults, Harry just tells Demonreach to seal her in the prison if she gets uppity. Mab's response? "Finally, a Winter Knight who is worth the trouble."
Molly pulling her life together in the aftermath of the last book's events.
Thomas's attempts to get Harry to reconnect with Maggie, reassuring him that he's going to be a great dad and talking about how they're going to get the cottage cleaned up for Maggie. They, like he's planning on helping Harry raise her. For a pair of orphans who never really knew parental love, you know these two are going to be an awesome father and uncle.
Thomas (and Mouse's!) attempts to get get Harry to speak to Murphy about their relationship.
While they don't get together, Harry and Murphy's talk in the cottage in Demonreach. Murphy tells Harry that they will never be Just Friends, reaffirms to him that she will always be there for him, and while now is not the time there might be a future to their relationship.
Harry's home was burned down in Changes. Since then the only places he's been able to stay were a boat, his grave, and the Queen of Air and Darkness' place at Arctis Tor. Shortly after coming back to Chicago he was attacked by the Fae. Molly shows up and rescues him. She takes him back to her rather impressive basketball court sized apartment, bandages him up, and gives him the guest room for as long as he wants.
(Regarding finding a place)
Harry:“Did you think I couldn’t take care of it myself?”
Molly:“Of course not, but...you know. I guess I think that maybe you shouldn’t have to? You were there when I needed you. I figured it was my turn now.”
The kicker? The guest room is designed and decorated just like his old place.
I looked around. It wasn’t home, but . . . it was in the right zip code. And it was maybe the single sweetest thing anyone had ever done for me.
Probably one of the most bizarre examples to date: Fix and Harry reaffirming their friendship after their fight. The fight was preceded by Harry's realization that combat was a foregone conclusion: Fix had spent years watching Lily, who he cared for deeply, be victimized in the worst ways possible by Lloyd Slate, and without any power of his own to stop him. Now, he had the mantle of the Summer Knight, and he was standing between Lily and the Winter Knight. He isn't seeing Harry: he's seeing Slate, only worse by exponential factors. As far as Fix knows (and Harry encourages this during the fight), Harry has become exactly the sort of monster that Slate was, but with the terrifying power that Harry has. The mere fact that Harry was deliberately defying what the Summer Knight's mantle told Fix he would do while still seeming to have succumbed to the Winter Knight's mantle wasn't a reassurance: it was a testament to the fact that Harry Dresden was everything Fix was so terrified that he would become if he ever signed on with Winter. All that said...when they talk afterwards, and Fix knows immediately how significant Harry shielding him from Lily's blast was, it's genuinely touching. Even in print, the naked relief that Fix gives off is palpable. Sure, he's scared of what's to come, but that's nothing next to what he'd feared mere minutes beforehand.
Harry's conversation with the Gatekeeper has a minor moment where despite everything that's happening to him, he still offer his help:
Rashid: I know something of the responsibilities you've chosen to take up. To say nothing of the problems you've created for yourself that you haven't found out about yet. And still, in the face of learning that our world spins out its days under siege, you offer to help me? I think you and I could be friends.
Note how they're calling each other by first name, too. It really hits home that they're friends, despite the difference in ages and stations.
Eldest Gruff shows up at the party early in the book, and Harry is genuinely glad to see him. Those two seem really close to dropping the "Enemies" part of Friendly Enemies. And we find out that he was the one who advised Titania to drop her vendetta on Harry, to boot.
While the winter mantle's sexually violent urges are extremely disturbing, especially when they end up directed towards Molly, it's noticeable that they never show up at all around Murphy. Murphy makes him angry enough to think about physical violence, but it never even occurs to Harry to assert his greater power through rape, the way it did with various other women, who had been much less confrontational than Murphy. Seems like The Power of Love is strong enough to completely overpower the primal force of the winter mantle.
Perhaps the Mantle just realizes Murphy would flipping kill its host if it got uppity enough to try it. Of course in Dresden's life, these are nearly one and the same.
Well, there is some very disturbing subtext while he's considering said physical violence. But yes, it is sweet.
Possibly Fridge Brilliance. The mantle urges him to rape the women he's around when they're tired, hurt, exhausted...in other words, it sees them as weaker, prey. But the thinking of Murphy as an equal is so ingrained into Harry's mind that it penetrates into the mantle.