"Robert Downey Jr really sells the idea of being a design engineer. To be fair, the Iron Man script does him the great service of having him have to build himself a new heart in a cave in Afghanistan, thus having to make imperfect things and fettle them to fit. That feeling gets slightly lost later in his super-engineer pad where apparently nothing needs filing when it comes back from the rapid prototyping machine. But he still manages to exude a kind of mad joy at making things, a fundamental character trait in the way that having nice breasts is not." Sophie on the emotional truths of storytelling.