It might have been introduced slowly over the course of the years as you recall this memory over and over. So that was a very cool but complex idea that we thought about representing in the film but could not find a way to make it work.

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.

And so not only did I have all new friends and all new surroundings, I didn't even understand what they were talking about, which was very difficult and kind of started me, I think, on my path to animation. It was a lot easier to draw people than to talk and interact with them.

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.

A lot of the issues I faced in junior high was what got me into animation. It was easier to sit on the side and draw cartoons than to engage with people.

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.

Yeah, we were looking for a way to represent adulthood and the passing into adulthood. And I think, for me personally and a lot of the folks that I work with, childhood is kind of a sacred, special kind of point in time that has a real joy and purity to it. And we sort of long on a daily basis to reach back and kind of grab onto that in some way.