As I was doing some brainstorming earlier at work, I had the weirdest stray thought. You know how sometimes you start to come up with an idea and it’s not fully formed at first, but over time fully develops? Well, I likened this process to filling a container (bowl, storage box, whatever) with a liquid. When you first pour it, there’s not enough to fill the bottom of the container, but as the container fills up it takes up the entire bottom and beyond.
In some cases memories seem to be much like this. The memory sparks, but not enough to fill whatever space the chemical substance that makes up memories occupies. But as you flesh out the idea or concept or plan or whatever it is you’re thinking, the memory chemical continues to fill up its space until the area is full enough to make you feel like the memory is complete.
This doesn’t always happen — only with memories that you have to work on a bit before they’re complete. It is one of the most odd feelings I know. It’s similar in nature to what happens when you remember something that’s on the tip of your tongue, but different, if only because your mind only feels fulfilled, but not rewarded.