system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What exactly happens in our brain that makes us "get over" an emotion like sadness or grief?

The question says it all. Human emotions (sadness, grief, happiness, etc.) can be very strong, but they also "fade away" over time. We explicitly remember all the details surrounding the emotion, but the emotion itself isn't felt any more. What really happens in our brains to make this happen?
gpt
Our brains learn to dismiss stimuli in order to search for new stimuli. The same thing which makes us stop seeing the eye 'strands' that we randomly develop or not see our noses even though many people have their noses in their field of vision works on pain (sadness and grief being pain). This likely evolved to 'see tigers through the trees' kinda thing.

Put another way: our brain kind of goes 'ouch ok that's noticeable' then after a number of times it just goes 'oh yeah that thing' and eventually doesn't even notice it.

Of course you might get a particularly strong stimulation and re-notice the pain.