Rilke wrote, “And it is not yet enough to have memories. You must be able to forget them when they are many, and you must have the immense patience to wait until they return."
In other words, it's the impressions that have sunk out of your conscious into your unconscious mind, and then risen to consciousness again, that might be useful to you as a poet.
Evelyn Waugh may have meant something analogous when he defined fiction simply as “experience totally transformed.”
V.S. Naipaul has written of his reinvention of himself as a travel writer -- “... that was another kind of writing, another skill. It could be as taxing as fiction; it demanded in some ways an equivalent completeness of man and writer. But it engaged another part of the brain. No play of fantasy was required; the writer would never regard with wonder what he had drawn out of himself, the unsuspected truths turned up by the imagination.”
Samuel R. Delany has commented on this phenomenon too --,
“Among those stories that strike us as perfectly plotted, with those astonishing endings both a complete surprise and a total satisfaction, it is amazing how many of their writers will confess that the marvelous resolution was as much a surprise for them as it was for the reader, coming, in imagination and through the story process, only a page or a paragraph or a word before its actual notation.”
“On the other hand, those stories that make us say, 'Well, that's clever, I suppose...,” but with a certain dissatisfied frown (the dissatisfaction itself, impossible to analyze), are often those stories worked out carefully in advance to be, precisely, clever.”