Where do all the thoughts go, if we forget them?

After thinking about this sentence for a while, I came up with two scenarios I want to tell you:

Part I

Your memory is like a big old writing desk, one of these enormous vintage-style ones with lots of drawers.
Some of them are open, others are locked and can't be opened.

The desk I imagine is completely covered with letters in different sized envelopes:
Handwritten ones which look personal, envelopes with typewriter letters on them. Big ones, tiny ones, white ones, pastel coloured ones, ones with black lining, on a few of the envelopes sport:

„IMPORTANT – DO NOT FORGET!“...

The envelopes which are opened and look a little bit worn out are memories.

They are usually stored in drawers which are crowded to overflowing and unlocked.
You can re-read them at any time you like.

Other letters aren't open and look still quite new.

These are your thoughts, your sudden inspirations, everything that floats around your mind constantly but without being concrete.

If you forget these things, it's possible that you will find them locked in one of the drawers which can't be opened again.

Also is it not possible to tidy up this desk.

Some of the letters are in the same drawer all the time. But others change their position constantly as if they are playing hide&seek with you.

I guess in a few drawers lies only one letter.
These are the things we wanted to forget. We keep them separately, so we will not be remembered suddenly when we are looking for something completely different.

We don't open these drawers often and if, it's mostly only short and without looking to closely at them.

The good thing is: This desk has the magical ability to offer enough space for endless amounts of letters. You will never have too many of them.

And this is my first imagination where the thoughts go, when we forget them.

Part II will be up soon, so sit tight! :)