irrational exuberance 1999
https://en.wikipedia.org/wiki/Dot-com_bubble
https://money.cnn.com/1999/02/23/economy/greenspan/

irrational exuberance 2018

https://www.cnbc.com/2018/08/20/after-the-bitcoin-boom-hard-lessons-for-cryptocurrency-investors.html

look where we are today!!!