I know exactly what that movie's [Brokeback mountain] about. I can't define it; it doesn't tie up in a perfect bow. But it's about adolescence. It's about what it feels like - this isn't meant as a criticism, but like things I didn't relate to, which were high school movies. Where I'd watch it and I'd be like, "Well, am I like the kid that nobody likes? Or am I like the person who everybody [likes]?" I couldn't [tell]. I was like quantifying, putting me in a box. "This is my personality at that age" and "I'm this kind of person" just felt like bullshit to me.

As Uta Hagen would say, there's the representational actor and the presentational actor. My sister [Maggie Gyllenhaal] came up to me recently after she saw this movie, Southpaw, the movie I did, and she thought there was this exploration of that type of presentation, and a bit of representation as well, if I could be totally honest, where she was deeply moved.

To me Donnie Darko was about adolescence. And about how, as soon as you start to grow up and you sort of move out into the world, you realize everything is so trippy. That anything can be anything.

My mom would always say this thing about writing - and I've taken it into account in a lot of things in my life - which is just, "Make it shorter." Figure out what you are truly saying, whittle it down to the essence, then say that.

I think that I have done work where I feel like I've challenged myself, and then what's even more confusing is I've done work where I think I've challenged myself and no one's responded to it, and no one's interested in it.

There are lines that just stick with me, like I mean I still can remember it's like every line that I say from Nightcrawler, I mean it's just always there.

The truth is most of the films that make a lot of money no one remembers, and I'm not interested in making films that no one remembers.