This man lost 25000$ by leaving cryptos in an exchange.

 Never go to sleep leaving your money in an exchange, always withdraw them to an account to which you have control of privatekeys.

https://np.reddit.com/r/CryptoCurrency/comments/6jd05d/someone_logged_in_my_poloniex_and_did_malicious/

Please follow me, resteem and upvote to get more stuff like these.