What's your worst Altcoin investment mistake?

[Quart]

I have failed to invest in many altcoins during 2018. Unfortunately, I tried to invest when crypto market started to decline gradually. If I calculate my funds, I lose more than 200%. Till now, I just hold the coins because the price so cheap. I will trade them only when the market rise again.   

[sixexgames]

I got involved with one of those cloud mining pyramid schemes. I was just a day from being able to withdraw and the site went scam and shut down.

[Crypto Guard]

The worst investment mistake in Altcoin for me is when I am investing. So I invested in Altcoin which was still cheap and the coins were not very well known, so I started investing and hoped this coin would improve and continue to improve in the future. After a few months, it turned out that the coin was dead. yes my money is gone.