You know there's always that kid in your class — and every class has one — the kid who draws all the time and is really good? That was not me. I was a lousy draftsman. But as soon as I figured out that I could make things come alive, like using the corners of my math book to make flipbooks, I was hooked.

And as I was sort of doodling, I was thinking, surprise and fear - probably fairly similar so let's just lose surprise. And that left us with five.

The way real memories work, from what we understand, is really complex. And it's an interconnection of different things and redundancy in the brain. So the idea of a memory existing as a little snow globe - the way we represent it in the film - is actually not scientifically accurate at all.

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.

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.

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.

In the end, passion and hard work beats out natural talent.