Rob: It’s on a neutral territory, there is also innocence to it - 

Seamus: Of course, it’s like two kids talking about their feelings.

Rob: The purspose of the scene (…) which is, you know, “I wanna be your girl, I wanna be your girfriend, I wanna be that special person. And I will as soon as I get this thing out of the way because I can’t commit for both”; and it gives Castle, you know, a reason to hung in there. But there is no doubt that he has been very patient with her struggles, but it’s just a testament of how much he loves her, which I think it’s…incredibly cool.

(Rob Bowman, Jon Huertas, Seamus Dever, and Tamala Jones episode commentary - about the swingset scene)

“Just really quickly, if you know me, and you guys - you know me, you know that I don’t like to learn anything. But despite my best efforts, I have learned in 100 episodes how much I rely - on how heavily I rely - on all of you. When people tell me, and they do, that they love this show I don’t think of the polished piece that we see on TV, I think about the hours we pull, the freezing outside, the laughs, hanging out, and being here. And I appreciate you all, and I look forward to coming to work and being with you all, all the time. Thank you very much.”

- Nathan Fillion speech to the cast and crew of Castle during the party for the 100th episode

If you could play any superhero in a movie, who would it be?

“Rob Bowman, who’s one of our executive producers, directed Elektra and I didn’t know that. Elektra was the first character ever that I auditioned for. I was so new that I drove down from Toronto to Chicago to read for the role, at 18 or 19. I thought that was a really neat piece of kismet. And then, Frank Miller drew me as Elektra and gave me his personal edition of the Elektra comic book that he had drawn.” (x)

Castle season 4 - “Linchpin” BTS (x)