It's very difficult for me to see films when I'm working. I get too easily depressed. If they're bad, I begin to despair for filmmaking in general. It seems proof that it's impossible to make a film. You're always plagued by the question: Can
we do this? So to watch a film that doesn't work is dispiriting, in a large sense.
When I watch a bad film, I often see it doing things that the film I'm working on is doing. It's like being a hypochondirac listening to medical discussions on the radio: Yes! I've got a rash right there too! That cough I had two days ago, it's proof! But this is a kind of madness, and it leads me to make wrong equations: Since such-and-such a technique is in a film that doesn't work, it means that if we're using a similar technique, our film won't work either.
On the other hand, if I see a film that I love, I think: I can use those techniques -- and I become like a magpie. It's like that crazy period in Victorian architecture when they ransacked the world -- These pineapples from southern India are marvellous, let's put them here! So when I'm working on a film, I like to see documentaries, and I like to see theatre.
from The Conversations: Walter Murch and the Art of Editing Film
by Michael Ondaatje