Well, the film initially - we had decided to pair joy with fear because I don't know about you - for me fear was a major motivator in junior high. So we thought there's probably some good stuff there... As the film went on, we had developed all these great scenes that were really funny, but in the third act, it wasn't adding up to anything.

The idea kind of started with me just thinking about what would be fun to see in animation, you know - what have I not seen? For some reason, I got thinking about the human body and realizing, well, I've seen, like, traveling through the bloodstream and into the, you know, stomach and things.

Dr. Paul Ekman, who worked in San Francisco - still does - which is where Pixar Animation Studios is, he had early in his career identified six. That felt like a nice, manageable number of guys to design and write for. It was anger, fear, sadness, disgust, joy and surprise.

Sometimes suffering is a weird attraction.

Well, we try to - we definitely try to have a balance. And I think things have gotten a lot better at Pixar. When we did "Toy Story," that was an all hands on deck situation that really was time intensive.

It's, like, you know, if you're sad, it's a way of connecting with other people. And we - a lot of times we sort of feel embarrassed by being sad, and we go off by ourselves to hide and cry by ourselves. But, really, it's a way of re-establishing relationship.

Well, the film initially - we had decided to pair joy with fear because I don't know about you - for me fear was a major motivator in junior high. So we thought there's probably some good stuff there... As the film went on, we had developed all these great scenes that were really funny, but in the third act, it wasn't adding up to anything.