There's a lot to be said for making it up as you go along. There's also a lot to be said for revising what you made up while you were going along.
Creativity is not the product of focus, although focus is indispensable to creativity.
Creativity fills an empty space. Focus doesn't create an empty space. It's amazing what can fill a second's worth of nothing.
Yes, perspiration is essential but inspiration can't be forced.
The inspiration for this: playing Pacman. Those few hundred milliseconds between relief and renewed vigilance. Researching and thinking hard before the game - and then the payoff, the sense-making, in-between the momentary triumphs.