system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we vomit when we see or smell something that is disgusting or uncomfortable?

NSFW just in case.
gpt
I saw an article once that suggested this is an evolutionary response. Imagine life in prehistoric times, or maybe going as far back as the common ancestor between apes and men. Nobody knows which plants are poisonous and which ones are safe to eat. A bunch of us are sitting around eating and someone gets violently ill due to being poisoned. If we're all eating the same plant, it's too late for the guy who got poisoned but it might not be too late for the others. Those who get grossed out and throw up stand a better chance of not getting poisoned. Evolution selected for the ones who puked.