Scammers want to get rich over night, these are lazy person that dont want to work, but want to be rich. Here are some kinds of scams I encountered on Bitcointalk.
1. Scam ppl when exchange money with them.
2. Use other person works for bounty payment.
3. Sending phising emails or message to scam.
4. Airdrop scam
5. Scam ICOs

I wish all those scammers go to the hell and will never has children.