What's the worst mistake you did with your Bitcoin? It can vary from starting to use Bitcoin to buying dumped Altcoin to gambling.

The worst mistake I made with Bitcoin is... Buying cloud mining hashrate. I bought 0.02 GH/s CEX.IO hash rate voucher at SEOClerk for $2 USD - or maybe $1 USD. I thought with 0.02 GH/s, I would be making a profit in half a year.. And I was wrong.

Well, I bought using the free five dollars coupon. So that does not count as making a mistake with Bitcoin. However, the slow profit lead me to buying hashing power from CEX.IO and later on.. ZeusHash using the Bitcoin I earned from signature campaign.. Again, I thought I would be making profit in a few months. Till today, I'm sure I have not make any profit from both the company yet. CEX.IO stopped their cloud mining operation and.. ZeusHash.. What do you think.?

Edited (15 May 2016):

First edit since this thread was posted. Anyway, after reaching more than 100 pages (103 to be exact), today I will list down some common ones.

1. Gambling
2. Not knowing Bitcoin earlier.
3. Participating in HYIP & Wrong trading technique (both Altcoin and day trading).
4. Sending to wrong address & lost of wallet.
5. Cloud mining & scammed trade.