system
Given the following post, respond as if you're commenting on Reddit:
human
Why isn't the ISS spun for "gravity"?
gpt
The absence of (apparent) gravity is the main feature of the ISS. Why would you want to ruin that?

There was a proposed single module that would have rotated to generate low (~1/3 g) appparent gravity for astronauts to sleep in, but that didn't make it to the ISS.