I love making fiction films as well as nonfiction ones, and hope to keep challenging myself to make better and better work.

I have always been interested in garbage: What it says about us. What in there embarrasses us, and what we can't bear to part with. Where it goes and how much of it there is. How it endures. What it might be like to work with it every day.

Some documentaries are made by people who are driven more by one particular story, or have different backgrounds or ambitions, but I'm always looking for projects that let me be the best filmmaker I can be, and to be stretched and grow further.

I love great locations in movies, and I couldn't believe I'd never seen a landfill on screen before. It was the most haunting place.

There's a theory of accidents that I studied when I was making a film about nuclear weapons: you can never eliminate accidents, because the measures you introduce to prevent accidents actually produce more accidents. That's certainly true of this sport; you're flying over 40 feet of what might look like snow, but it's hard as ice, it's as hard as pavement. You're doing acrobatic spins and tricks, 40 feet above pavement, essentially. There's been more accidents since, and there are going to continue to be more accidents, that's the nature of the sport.

Why is nobody questioning the sanity or suicidal tendencies of Everest ascenders? It's kind of a question of framing: How do you frame these activities? We frame them as freedom-loving, exciting, progressing sports and they are. But there are other ways to frame it. It's also true that these young men, neurologists say that their frontal lobes aren't developed yet - the long-term planning part of the brain.

I can ask someone to let me into all aspects of their life for several years, but people have got to have that gift: that courage and that talent for opening their lives to the camera. Being candid is a gift, and that's what the audience responds to. Part of it is me asking, and part of it is just their inherent talent, which is what you are looking for when you make documentaries - people that are really going to let you in on what they are going through.