Shortly before the dot-com bubble burst in 2000, Princeton University professor Robert Shiller wrote a book called Irrational Exuberance.
The title came from a quote by then U.S. Federal Reserve chairman Alan Greenspan.
Now, some might wonder if there's some irrational exuberance in connection with the world's most famous cryptocurrency.
As of today, one Bitcoin is worth $72,962.46 in Canadian currency.
That's up 92 percent since the start of 2021.
The rapid run-up came before and after Tesla CEO Elon Musk announced that his company was investing US$1.5 billion in Bitcoin.
This week, Musk admitted to Bitcoin critic Peter Schiff over Twitter that the price of Bitcoin and another cryptocurrency, Etherium, does "seem high".
Earlier this week, Schiff said in a Zoom interview that Bitcoin buyers don't know it's a bubble so they'll never sell. That's despite fewer merchants accepting Bitcoin now than they did in 2017, according to him.
"I've never said that the price of Bitcoin couldn't go up," Schiff says in the interview below. "I mean, if people are dumb enough to pay $50,000, maybe someone will pay $100,000. I don't know. I don't know how stupid people are going to be."