I think players tend to get anxious if they've not really done things properly - like eating, resting or training. If you're fully prepared you've got nothing to worry about - it's just a game of football.
“There's a tendency on the part of Americans, all of us, to say, 'Hey, the Cold War is over, the Soviet Union is gone, we don't have to worry about these guys again.' We always have to be worried about them, we always have to be concerned about them, and we have to be well-informed.”
“At dramatic rehearsals, the only author that's better than an absent one is a dead one.”