It was fun figuring out the science of the world as much as we wanted to figure out, and then playing fast and loose in other places. Which we do with our show in general. One of the things we love about the BoJack Horseman show is that we can always fall back on, "It's a ridiculous cartoon." And it is! It's a serious, relationship-based grounded character tragedy, but it is also a ridiculous cartoon.

One of the things I've found really interesting about the show is that a lot of people really relate to our animal characters, more than we thought they would. Part of that is, because they are animals, people project themselves onto them. If BoJack just looks like Will Arnett, people go, "Oh, I know who that guy is. That's a Will Arnett type." But because he's a horse, people can go, "Oh, I'm kind of like him in some ways."

It's really cool to get these guests on the show BoJack Horseman: not just actors, but, "Can I get Jonathan Lethem on my weird talking horse cartoon show to talk about how growing up in Brooklyn, he always dreamed of being a ringtone?"

In a certain way, sometimes it does feel like we say goodbye to a character, and we don't want to bring them back unless we have a good reason. We left the door open if we wanted to use him more. I always think it's better to leave the audience wanting more.

Jessica Biel is a really interesting case. She actually called us after the table read and said, "You guys should go meaner." She pitched us, and said, "Look, I know there are a lot of things to make fun of me about. I don't want people to think you're pulling punches. Please, dive in." We asked, "Could we tell a joke about your friend and mentor Stephen Collins?" And she said, "Well maybe not so much in that area. As long as the jokes were about me, I'm game for everything."

The beauty of Netflix is that you can figure out a good part of the season before you get started. You're never in the hole of, "Oh, we've already released the first four episodes, and now we gotta make the finale, and we've already promised this."

Daniel Radcliffe was actually a fan of the show and excited to be on it. Some of it is we've gone long enough that we're legitimate. Even if they don't know the show, they know we are a show and not some weird thing that's going to go away. Also, the more celebrities we get on BoJack show, the more it feels like a club to be in: "If Naomi Watts will make a fool of herself, I guess I can make a fool of myself, too."