system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: how does remembering a dream work? How does that fit with long term and short term memories?

Sometimes i can remember a dream, sometimes i can't. Sometimes something will spark me remembering a dream and the longer i think about it the more, i can remember.
gpt
There is a part of your brain that tests reality.  You are walking down the street and see a man with three arms, and that part says, "whoa, that can't be right, let's take a closer look and figure that out."  You do, it turns out to be two people standing at a funny angle, and all is well.

When you dream, that part of your brain operates at a reduced capacity, and doesn't question the implausible as much.  You are an adult but still in elementary school, you are in a rocket to space, you are pitching for the Yankees, your brain just accepts it without asking too many questions.

This leads to dreams that seem to make sense when you are in them, but fall apart when your logical mind awakes.  It might make perfect sense in your dream that you had to pitch for the Yankees because you lost your shoes on the bus, but when you wake up and try to put that into a logical framework within your memory, it all falls apart.

Also, when we dream, we often dream in impressions rather an actually sights and sounds.  If you have every dreamed you were driving a car, what kind of car was it?  Was it a stick or automatic?  Two doors or four doors?  What was playing on the radio?  Chances are these details were left undefined, and the only parts of the car you were aware of were the steering wheel and pedals.  The rest remained this abstract concept of a car, that left you impression the details were there, when they were not.  Since it is those very details that help up build memories, their absence makes remembering dreams more difficult.