Scott Adams, he of Dilbert fame, writes about his terrible memory and it sounds oh so hauntingly familiar:
In school, I could force myself to remember topics for tests, but it only lasted as long as the test. At home, we have a lot of conversations about what I might have heard or said at some specified time in the past and it almost never sounds vaguely familiar. Sometimes it feels as if someone else lived my life until this very moment and now I'm taking over.
The way I perceive the act of creativity while it happens in me is as a process of forgetting, not a process of creating. The mind is not capable of having zero thoughts, so when you flush whatever is in your head at the moment it creates a sort of vacuum that sucks in a new thought. In my case, that process of forgetting and then sucking in a new thought happens continuously. My memory isn't "sticky," so what comes in slides right back out in a nanosecond. Sometimes a new thought is worth writing down, which I either do right away or lose it forever. Usually the new idea is random garbage and it passes quickly, making room for the next idea. My mind feels like a slot machine that I can't stop pulling. Sometimes the diamonds line up, but not often.