The worst mistake I did with Bitcoin is playing gambling and lost almost 6 BTC just in minutes.Gambling is addictive and in the end it let you without money.This is biggest mistake I did since I started using Bitcoin.
I wouldn't gamble with any money especially not bitcoin. Would prefer to hold. I;m not sure what my biggest mistake is. I guess everyone says they should have bought more but the profit wouldn't have been that good for me as the price currently stands.