From https://twitter.com/LipBitinANNAmal/status/1078840770864529408 156,700 Retweets 376,681 Likes (probably not the original author):
How old were y’all when you found out the ridges on the bottom of the salt/pepper shakers had a purpose?
[Video of a shaker not dispensing much, until two shakers were rubbed against each other]
Can the ridges on the bottom of shakers be used to help with dispensing?