Let's just say that I bought into a lot of ICOs which climbed to ridiculous levels, and then crashed down to almost nothing. There were others that I bought where the company just stole the ether and disappeared.
One of the few coins that I'm still holding onto is Enjin. I still believe in this project. But it really hurt because I bought a couple million coins at between 0.01-0.015 cents. It got all the way up to over 50 cents at the beginning of the year - which made me an instant millionaire; but now it is down to around $0.05 USD. So still a gain, but main did that hurt!