system
A chat on subreddit /r/me_irl
human
The .7 is amazing. The .10 is wayyy too thick and .5 is far too thin.
gpt
You are incorrect. 

0.5mm is perfect.

It's the 0.38mm that's too thin.

I personally think 0.7mm is too thick, but is acceptable if nothing else is available.

1.0mm is insane, I'd rather just write with a sharpie at this point.