system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we feel the need to scratch itches when it rarely benefits us?
gpt
Firstly: It seems to be an instinct. All sorts of animals do it, if they have limbs that support scratching.

Secondly: It's still worth it those few other times. Bugs, Parasites, parts of plants (poisonous or otherwise harmful), etc. aren't something that is beneficial to us. So why not scratch just in case?