system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do models scowl while on the stage ?
gpt
I remember reading somewhere a long time ago that it's supposed to be neutral expression, so as to ensure the models don't accidentally make funny faces and take the attention away from the clothes they are modelling. 

I guess some of them looked like they're scowling because they're biting their cheeks to stop them from making any sort of expression?