system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What makes us forget what we were literally about to say?
gpt
Our brains are poor data-storage and retrieval devices because it didn't make the difference between life and death in the food chain.

Consider all of the things that *did* make the difference and look how well developed they are:

 - You have excellent front-facing colour vision that can quickly adapt between high and low light environments.
 - You can tell where sounds are around you because you have excellent spacial-awareness and audio positioning.
 - You have opposable thumbs for gripping things delicately. And associated well-refined muscle groups for manipulation, allowing you to craft tools and get the most out of your food.
 - In an endurance race, you can out run nearly *all* other animals on planet earth.
 - You have built in parental instincts that make you want to nurture something with a cute face and large eyes, because it incentives us to protect our offspring.
 - You have built in senses of revulsion to things that look diseased, rotted or otherwise wrong to stop you from consuming it and becoming ill.
 - You have a lack of hair on your body to make parasites easier to detect.
 - When another human vommits you feel compelled to do the same to preemptively flush out the same poison.

Complex conversations with other apes however? For hundreds of thousand of years, nobody ever died because they took 2-3 seconds to remember the name of that thing they saw once. So it wasn't all that high on evolutions *things to adapt* list.