Imagine that the situation that you're looking for a creative solution for is a game with a set of rules. Write out the set of rules.
Who are the players (as defined in the rules)?
What is the balance of power? Who has the information, and when do they have it?
Who gets involved in the process? At what point?
How does each player behave in a given circumstance?
Now question the rules. How could you shift them? What actions would you have to take to shift the balance of power? What would happen if you changed who the players were or when people got involved?
Sometimes a certain amount of pressure can be invigorating, but can you honestly say you've ever had a good idea when you were trapped at your desk, sweating bullets, and thinking about the incredibly high stakes involved in your project?
It's a different, more subtle form of fear, but it's still paralyzing. Think about a more extreme case: Imagine the plight of someone who is trapped in a panic-inducing situation. From the comfort of distance, we can wonder, 'Well, why did he run toward the fire/deadly cobras/radioactive zombies? I certainly wouldn't do that.' Scale down the panic to the stress-suffused atmosphere in your office, and you can see that under the crushing weight of seriousness, the best decisions aren't being made. When your tunnel vision is setting in, you can't evaluate or even recognize a good idea.
When the stakes are high and you desperately need a powerful idea, that's the best time to try something light and playful. Even the most senior executives seem relieved when they can lighten up-if only for 30 minutes.
Creativity and imagination require that we play, that we be relaxed and free. Being overly serious can stifle even the most creative spirit, intimidating it into never speaking out.