It is the easiest thing in the world to love Nate Archibald. It's one of the things that Blair loved most about him, and it's one of the things that they all love about him. It's one of the things he takes with him when he stops loving you back. But then, nothing ventured is nothing lost. Chuck said goodbye to him when he said goodbye to Serena, and to the family: Nate's goodbye was lost in that, and they both knew it. And so, now that he's said goodbye to Lily, and last of all to Eric, there's only one goodbye left.
It is the hardest thing in the world to love Blair Waldorf. It's one of the things Chuck loves most about her, and it's one of the things they all love about her: the way she makes it worth it. She twists underneath it like a wild thing, afraid to give up too much ground; she knows that once she admits her hunger she'll never stop. There is not enough love in the world, in a person, to satisfy Blair Waldorf, and she knows that. Waldorf women have a magic too: her mother uttered a secret, ancient curse over her crib, when all the kingdom was asleep. Not. Enough.
But then, nothing ventured is nothing gained: there's only one prince in the world who loves her enough, who has saved up his love for all his life just for her, without knowing it, until it threatens to split his seams. They both know it could end the world. So they wrap it up in ribbons and call it by other names, and when it burns too hot they take out their knives and fight, to keep it from destroying them both. This is the last goodbye; the one that breaks them all the way open. For a moment she's running up that hill again, watching him hurtle toward the funeral; running headlong toward a private death. For a moment she can't speak.
"Chuck! Stop! Don't go. Or if you have to leave, let me come with you." He unsteadily assures her he's grateful for her concern, and she shakes her head. "You don't appreciate anything today. But I don't care." He begs her to stop with his eyes, hears the train coming, but she knows better. "Whatever you're going through, I want to be there for you." Chuck throws it in her face, like a crucifix, threatening now: "We talked about this. You are not my girlfriend."
Waldorf women have a magic, too, and she knows when it's time to break it open. Find the right words, sing the right song, just softly enough that he'll stop, and rest, and be calmed. Remind him of himself, drag him back across the line: "But I am me. And you are you." He starts shaking again; she takes his hand so tenderly he won't notice. "We're Chuck and Blair. Blair and Chuck." The right words, as he's breaking in her hands: find them. "The worst thing you've ever done, the darkest thought you've ever had... I will stand by you through anything." Chuck scoffs: "Why would you do that?" Why would anybody? Why, after the last goodbye, would anyone follow him where he's going now?