system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does my nose get so used to a smell that I can't seem to smell it after being in the room with it for a few minutes?
gpt
it's not your nose, it's your brain. your brain is permanently filtering data which it classifies as "not necessary at this moment". if that smell doesn't change your brain decided at one point that this smell seems to be normal - and normal things are not really important, normal things will not harm you or at least you know how to handle these things. your brain is focused on unexpected, unusual things which might be dangerous.

it's the same with a continuous, never changing sound - first it seems to be annoying, loud as hell and everywhere, a while later you don't hear it anymore.