The drive of the story is sort of hinted at the beginning, is Joy and Sadness and those two characters. Especially Joy starting to understand that there's more to life than being happy. And so that's based on real life observations and things that we've learned as adults.

Anger is about fairness. If it feels that you're getting ripped off or taken advantage of, that's when anger comes up. Sadness deals with loss. And I suddenly had this new revelation - it felt like to me - that those are all true, but the real, deeper reason we have emotions is to connect us together. And that felt big to me.

You have to think about good storytelling and characters first. Then hopefully, the rest of that stuff will follow, some more than others. But if you don't have a good film and strong characters, then you don't have anything down the road.

There's something really emotional about not having any sound. That allows, I think, the audience to participate more actively and kind of imagine what are they talking about there?

So this idea of moving seemed like a good way to sort of represent that metaphorically. It also is something for me personally. When I was in fifth grade - so about 11 - my folks moved us to Denmark.

And it's about a three-month process every screening. And that way we have seven or eight chances at the film before we have to actually build the models, build the sets, do the animation and all of that. So it's a - I think that's a real key to the way we make films.

And it sort of hit me that the very subject matter of the film that I'm dealing with is the key to the most important thing in our lives, and that's our relationships. And so we had done all this research showing the job of each individual emotion, you know, fear keeps you safe. It deals with uncertainty.