He seems to chose roles that allow him to be his off-the-cuff self, or at least, the off-the-cuff self that he and his people want us to believe that he is. He is the anti-Tom Cruise: Cruise chooses empty roles that he then disappears into, while Downey leads with his persona and lets the role fall around him. Iron Man would be far less dynamic of a series without him. Tony Stark’s spoken refrain is Downey’s implicit one: He is Iron Man. But in the end, that’s nice and fun and good for him, but nothing much beyond that.