[jzb]

Not limited to recent slang, really - consider all the early 1900s slang that's now part of the language. "Bee's knees," "beat it," "cat's meow," and lots of others. Somebody tested out those phrases and they stuck.

"It sounds cool and kids' parents hate it" goes back to at least the 50s. It's an arms race of kids/teens trying to invent their own slang that their parents won't understand and then that language being picked up in popular culture and becoming more widely used and then kids try to come up with new terms.

(We had a lot of fun with "yeet," "hype," "been knew," and a few others with my kids a few years ago.)

[drewzero1]

Cockney rhyming slang also comes to mind. I have to believe "it sounds cool and kids' parents hate it" goes back even farther than that though, probably ever since there have been kids and parents!