I love the ups and downs and the eccentricities of my career. The worst movies have produced some of the best friendships.

I'm on record as having said "I've done this amazing movie - The Sixth Sense - that no one is going to see." And then it stayed in the top 10 American films for about six months. So don't ask me. I'm the most disastrous PR and marketing predictor.

The phrase you usually hear after a cut is "That was great. Perhaps we could have another go. Maybe try it this way." Even that much direction is prefaced with a lot of praise and encouragement. It's quite like how you deal with toddlers: positive reinforcement, and then a little suggestion that you might want to try something different. Roman Polanski will stop the take and shout, "No, no, no!" Which is somewhat alarming the first time it happens.

My agents were like "Come to L.A., we've got meetings for you." I was like "No, I'm doing this now." Then my father became very ill back in England, and I didn't want to be away. I went back to England and did a bunch of crazy indie movies, all of which I loved with a passion, and none of which did any business.

Roman Polanski actually said as much to me once. He had his head in his hands, and I said, "Roman, I've got to tell you, as an actor, seeing the director with his head in his hands... Look, I really want to do what you want me to do." And he went away and he came back, having obviously thought about what I said. And he said, "When my head is in my hands, I'm closing my eyes and trying to remember what I saw in my head, before any of the stuff."

Joss Whedon writes beautiful drama. His sensitivity and his sense of drama and scenes are pretty exceptional. There's no one else writing like him, really, in sci-fi and TV. That's not to say there are no astonishing writers on TV. I was nervous about coming to America and playing an English person who speaks very English when all the writers are American, because it's a very particular thing to imitate, and if it's badly imitated, it sounds painfully contorted and silly. And he writes very well for English people. It was Joss Whedon who persuaded me.

It's funny, when people want things to be very truthful and you're dealing with an inexperienced actor. I'm of the school that believes things like that have to be very carefully choreographed. You need people there to say, "It's going to happen like this."