The farmer makes a clear separation between growing and harvesting.
The process of growing requires investment in nutrition, protection from pests and most importantly, patience. When the vegetables begin to appear, the farmer exercises restraint. Harvesting them too quickly could mean that they are not big or ripe enough. Too late, and they could rot before they are sold in the market. All this while, the plants grow on their own terms, with the farmer facilitating this growth.
In the creative process, every new idea is a sapling. It needs to grow and mature before it turns into a plan. During this growth stage, the idea assumes a life of its own, just like a plant. This should be nurtured rather than pruned with judgement or criticism. A good brainstorming session welcomes all ideas, regardless of how radical they are. A seasoned writer separates the creative process of writing from the refinement that comes with editing.
Surely, critical thinking plays a crucial role. But bringing it too soon to an idea is analogous to harvesting the fruit even as it is green and underdeveloped.