So this thread is one of my most successful one at Bitcointalk with over a hundred pages or replies. Anyway, first edit to the first post was made.
Listed down some common mistakes people made with Bitcoin.
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.
Since i don't gamble no 1 doesn't apply to me. But no 2-4 are things i recognize. If I could do it all over I would have saved at least 4-5 bitcoins.
For me was learning money...
Yeah you need to learn new things and also find the safest way to earn money which can be profitable in future and you don't have to bear losses by investing in gambling.