When I was a kid, whenever we pulled goofy or grumpy faces, our Mum would tell us that we'd get stuck that way if we weren't careful.
She wasn't the only source of such sage advice; I'd read something similar in one of my favourite books by British author Enid Blyton. In Adventures of the Wishing-Chair (1937, Newnes), just as an obnoxious little boy pulled a grotesque face, the wind changed and he couldn't change his face back. *gasp*
Lucky for him, intrepid Mollie and Peter and their Wishing-Chair managed to track down a bit of the original wind to blow back in his face. Lo and behold, the boy's face was unstuck and off he went, hopefully never to make faces again.
According to some discussion thread on the Internet, the your-face-will-get-stuck saying dates back at least the 1800s and may or may not have also involved a clock chiming 12 as the winds change. I see it as just one of those old-timey ways to teach kids social niceties (unless said kids love bathroom humour and attribute another meaning to the word "wind"). But I bet it's not something kids today have ever heard.
Regardless, I clearly haven't learned my lesson. I make faces a lot, especially if I'm snapping selfies, or smell vanilla or bananas.
Perhaps I should apologize for posting my contorted mug in such a large size...it's scary, I'm sorry! *grin*
Were you told something like this as a kid? Have you passed it along to your own kids if you have them?