system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do humans forget important things, but maintain embarrassing things like when we called our teacher mom?
gpt
Negativity bias. For whatever reason, the brain seems to put more emphasis on negative things than positive things, even when both things are equally intense. For example, losing $20 will seem more significant than gaining $20.

Because negative things seem more significant, they are more easily remembered and weigh more on your mental state.

Side note, that's why bad news seems to happen more often than good news. People respond more to bad news, so it gets spread more.