Rather than opera, football is more like ballet or a chess game. You can really see it in a team like Arsenal, especially when Dennis Bergkamp was playing. He seemed to be able to read the game like a chessboard and knew where a player would be several seconds later and put the ball there for him.
The wonderful thing about maths is it's a totally logical subject, and a pathway has been marked out. I think a lot of these things can be crystallised in something quite essential, that people can get. If I can't explain it, I realise that's probably because I don't completely understand it myself.
If I'm flying to China, I can sit and think about a problem. Other scientists have to go to the lab. I'm always thinking about maths, even when I'm doing other things. A lot of the time you're going up blind alleys and it's very frustrating, but then you have a sudden rush of ideas. You can live off that for quite some time.