I mean, I've - these other films were flukes. I don't know what I'm doing. I should just quit. What would I miss? I'd miss my house and I'd miss going to work. But I think the thing that I realized I would miss most is probably similar to everybody, which is your friends.

People are funny -- they are able to project personality onto anything. I remember as a kid I spent a $ 5 bill once and felt so bad because the other $ 5 bill was now going to be lonely without all the other bills I had in my wallet, you just invest these dead things with life and that is our tendency as people. So animation takes advantage of that, grabs on to it, and runs with it.

Well, what if we did this in the mind as opposed to the brain? So instead of blood vessels and dendrites, what if it was consciousness and dream production? And that would allow us to have characters that represent emotions. And that felt like, man, that's exactly what animation does best - strong, opinionated, caricatured personalities. And that just got me excited.

However, for story reasons, we needed to represent them in certain ways. One of the things that sort of blew me away that I didn't know when we started is that memories are completely susceptible to change. And this is, you know, one of the many reasons why certain people are trying to get it taken out - eyewitness testimony in court cases because it's very unreliable.

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.

It's like you run into this dark tunnel, trusting that somewhere there's another end to it where you're going to come out. And there's a point in the middle where it's just dark. There's no light from where you came in and there's no light at the other end; all you can do is keep running. And then you start to see a little light, and a little more light, and then, bam! You're out in the sun.

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?