The flash crash of Ethereum was not about emotions. There was a real technical issue. According to Zerohedge there was a ICO (initial coin offering), which is horribly gone wrong. Ethereum was sliding from $360 to $260, then flash crash to $0.1 and come back to $317 today.

http://www.zerohedge.com/news/2017-06-21/ethereum-flash-crashes-after-status-ico-clogs-network