system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why salt improves the taste of almost everything.
gpt
It's because us humans enjoy the taste of salt. It's one of the most important things a human needs, and because of that we like to taste it. When humans were a young species, salt wasn't easy to find. Most plants that we could eat didn't have it in the amount we need; animals did have it though. 

When we ate animals, our tongues told our brains that we liked salty flavors, and we decided we needed more of that because we liked it so much. This made us look for more animals to eat, which gave us the salt we needed.

Without salt, we'd all die. It helps electricity get through our blood, which lets our muscles talk to our brains. Without this salt, our muscles would stop working. Our heart is a muscle, so if we stopped eating salt our heart would stop working and we wouldn't be alive anymore.

Because we need salt so much, our tongue changed over time to make us like salt. This is not such a good thing nowadays, since we have so much salt. When people ingest too much salt, we sometimes get high blood pressure.

Slightly less ELI5 answer:

Sodium is totally an important thing. We've evolved over millions of years to appreciate the taste of salt because it's a vital compound. Without salt, our nerves couldn't conduct properly, and many cell functions depend on sodium ions.

Long story short, organisms developed a taste for salt because it's so incredibly important for life. Without a predisposition towards salt, we would have ate the wrong food sources and died. Natural selection guided toward a predisposition to salt.