I haven't ever lost bitcoin neither my bitcoins were stolen as of yet(Touchwood). But I have heard many many cases where not just bitcoins but mamy other coins were stolen from them from exchanges and ICOs. If I remember quite correctly one of my colleagues was an investor in some ICO called as circle or something similar and that was such a big scam, the signs were clear and the returns promised were quite to high and no I had never seen an ICO claiming things like the Circle ICO was but people still wasted there time just because of that greed of money. Lol shouldn't be laughing on people's misery but it is always those peope who are greedy of money are the ones who get scammed more often.