Get 10 friends.

Run into a McDonald’s and shout “Everyone get the MC Turd smoothie!”

Idiot buys it.

Do that a bunch of times over and over, with more idiots buying it.

At some point, someone realizes the MC Turd Smoothie tastes like poop. But it’s too late. You have too many idiots holding it so now they’re the 10 friends.

That’s the stock market.