"He was actually the first person I had in my head," she replied. "Actually, he was the only person I had in my head when I was writing the role. The other characters were really blank slates, but Seth for me really grounded the film. He's a comedian I've always loved, and I felt like as a fan of his, I really wanted to see him do something dramatic. So in a way, for me, it was really selfish to write that character and base it so closely on him. I also wanted… when I started writing the script, his character was the one I related to the most. I wanted it to be somebody that we can really love." I know when I mentioned Polley on Twitter recently, Seth was one of the people who both favorited and retweeted the comment. It makes me happy to see that there's still fondness between them after working together. That's not always the case, but it seems like that was a really good experience for both of them, and I love the end result.

Now, in discussing "Stories We Tell," there are some elements of the film that you don't want spoiled for yourself. If you're super spoiler-sensitive, you should bail out here until you go see the film, and then come back. Basically, I wanted to discuss with her how this new movie, which is a documentary about something she learned about her own life, plays a long-con game on the audience that blew my mind, and I asked her how she came around to that as the approach to telling this story. Basically, the film pulls the rug out from under the viewer at a certain point and you realize you're not watching what you think you're watching. I asked how she even began to work out her approach to the storytelling and what she shot for the film, what archival footage she used, and how she decided how to intercut the interviews.

"I think my main idea was to give the audience some sort of parallel experience to the one I had when I was unearthing more and more details, some of which conflicted with each other, and hearing more and more information that threw everything that came before it into a different context, revealing very different meanings." I love that even though she's talking about some fairly major and cataclysmic events in her own life, she always felt very matter of fact about it, never trying to elicit cheap sympathy. "I never felt when I was trying to investigate the story in my own life that I was ever on solid ground, and that I never really knew if what I was hearing was fact or was it a memory imbued with nostalgia. What was it that I was experiencing? And so I was trying to find as many ways as possible in the construction of the film to give the audience a parallel experience. I wanted there to be questions about what they were seeing. And I felt like if it was all linear and straight-forward, then I wanted to give them another piece of information later that would make them question pretty much everything they were seeing."

I told her that the first time I saw it, I had to back the movie up because of the way she almost casually shattered my understanding of what was "real" in her movie, and she started laughing. "What moment was it for you?"

I told her that it was when she suddenly stepped into a frame with somebody that she couldn't possibly be in a frame with, shattering the notion that a certain strata of the archival footage we were being shown was real. She laughed even harder at that. "I'm so glad."

She's been screening the film, so I asked if she's able to hear people react as they start to get what's going on, and if it's something that is noticeable in the theater. "Yeah, there is," she said, "and it's really been fascinating for me because we did do everything we could to match as closely as possible to the archival footage that we had, and we had an amazing hair and make-up department and an amazing wardrobe department to help us do that, and of course the actors, but we were pushing really hard."

She laughed at the thought of it. "The ambition was to make people sometimes wonder if what they saw was real or if it was fake, but I don't think we ever thought that it would work well enough that it was a big twist in the film when people found out. So that was amazing at those first screenings, and to hear people respond like it was a big revelation was a big revelation to me that it could be a revelation. So that was a really exciting moment for me, to realize that the film was doing more than you even thought it could. It was really kind of cool."

I commended her for the way she's carved such a personal career out as a filmmaker. Her acting has been in much broader-appeal films at times, like "Dawn Of The Dead," but as a filmmaker, she's made very personal films. Her next film is supposed to be an adaptation of Margaret Atwood's "Alias Grace," which is no easy task for any screenwriter. "Well, if I'm going to spend several years working on something, it's got to be something that I really love. I have ideas for films all the time that I don't end up making because I guess they don't matter to me enough. 'Alias Grace,' for example, is a book that I read when I was seventeen, and I've been trying to get the rights to it ever since. I've been imagining that film for so many years. I just can't imagine writing and directing and going through all the grueling hours that go into any film if I wasn't passionate about what I was doing."