Well, people buy diamonds and they're basically useless, other than signalling that the purchaser has a certain amount of money. The price for them is much inflated over what it would be if priced purely for their practical value. Artificial diamonds are identical to the naked eye, yet the diamond industry somehow influences our culture to make people think they need to spend many thousands of dollars on useless "real" diamonds.

On a (somewhat) related note, this conversation reminded me of a George Carlin routine: https://www.youtube.com/watch?v=MvgN5gCuLac