What kind of socks are you wearing? According to Gen Z, your answer shows if you’re a millennial or not. Tall socks, they say, are for the youth. Only older people (read: millennials) wear ankle socks.

Socks are the latest iteration of the Gen Z vs. millennial debate. But it’s not really about the socks, writes Business Insider’s Emily Stewart. It’s a reminder that millennials’ fear of getting older is an opportunity for companies to make money.

To fend off the march of time, millennials often try to keep up with trends. That means spending their way to youth, Emily writes. For brands, that’s a chance to sell — be it tall socks, injections, or anti-aging creams.

Capitalizing on people’s insecurities has long been corporate America’s sweet spot. Before social media, women and girls compared themselves to unrealistic beauty standards put forth by glossy magazines.

But TikTok and Instagram have changed the game, funneling every new trend directly into millennials’ feeds. It’s a constant reminder that they’re on the wrong side of a trend — or worse, the wrong side of their 20s.

As Emily writes, though, it’s worth keeping an eye on the companies that want to keep you chasing youth.

“They make money only if you buy something new,” Emily writes. “And making you feel like you’re falling behind the times or presenting you with a hot, new trend you have to keep up with is a way to accomplish that.”