I felt - for the first time - the exact moment when the endorphins kicked in. The rush through my veins when suddenly my pace, my breathing, my psychology changed. It was 2.5km into a run, off-road, 10pm, heavy rain. It was as I turned into the south-west corner of Hackney downs, where the road disappears behind rows of trees and the trail becomes a thin scratch of dirt. There was a wave of calm, a ripple that suddenly but carefully relaxed my legs and my rapidly beating heart. My feet suddenly felt lighter. My stride suddenly felt like it could go on forever. It was as if a giant hand was lifting me gently from the back of my shirt, saying, "take some of that weight off your feet."
And my psychology changed, my mood was lighter, my brain reacting to the sudden intake. There was a rush of excitement. I saw someone walking their dog on the path. The owner ignored me, but the dog looked up and followed me as I floated past. I waved at the dog, smiling.
I was able to forget, momentarily. The rain was warm.
I was thinking of the conversation I had had the day before with Abdelfattah, the man I followed for several weeks for my first documentary I See The Stars At Noon. I've stayed in touch with him since those days in 2004 when I filmed him as he tried to cross into Spain from Morocco's northern coast. I recently sent him a copy of the film, after six years. I wasn't ready to hear his opinion until then. Finally I gave in and sent it. He watched it almost immediately, and told me later, on the phone, "Saeed, this is a real documentary." I took it as a compliment.
"But why is it so sad?" he asked "You made everything look worse than it was."
"There are some good moments," I replied, perhaps slightly defensive. "The conversations we had, the time we sang together. But honestly," I explained, "the film reflects the way I was feeling when I made it. It was very difficult spending so much time with you, it was depressing. Don't you remember?" Yes, he said, he remembered.
Yesterday, he asked why I made films. "There are so many problems in the world, and you want to solve them all. You can't solve them all." He didn't believe that films could change things. I said I didn't want to change things, I just wanted to make good films, tell good stories. If one person came out of a film of mine with a better understanding, that was an added extra, but that wasn't my goal. If one person watched his film and said "now I understand something more about what life is like in Morocco," I would be satisfied.
"I think you need to sit down, quietly on your own, and consider what you're doing. I think there's something else you could be doing."
"But this is the conclusion I've come to after years of trying to decide what to do. This is what I believe in."
He didn't seem entirely convinced.