The mind is such a funny thing. One thought tends to trigger other thoughts. You have a conversation with somebody and you go from talking about the politics of philharmonic orchestras to the logistics of living in Barrow, Alaska and you have no idea how it happened.
It can be really hard to figure that out, actually. Somehow, once you get onto a new subject, you leave the old one behind. However, if you take the opposite direction and work forward instead of backward, you can jump start your memory.
I know I started with orchestra politics. That led to mentioning how the principal oboist isn't even good enough to deserve the leeway he's gotten. That made me wonder how much a player's skill matters and how much the quality of their instrument matters. That led to talking about the different materials an oboe could be made of, one of which being plastic. The plastic oboe is the one you would take to the frozen tundra so that it didn't instantly get destroyed, and that led to Barrow, Alaska.
Now I not only remember how I got there, but I remember all of the subjects along the way.
If you had a great thought and you just absolutely cannot remember it, try working forward to jumpstart your memory.
From my notes:
Most of my thoughts come flying at me, but they always have a rationale. If I can hop onto a previous idea and ride the train of thought, I should eventually reach the station (thought/memory) I was trying to remember.