We will explore, in detail, seven questions posed by the co-creator of Ethereum, Vitalik Buterin. The series was inspired by a discussion between Buterin and a WeChat group called "Mars Finance Global Family."[1] The seven questions address some of the most relevant features of this booming cryptocurrency ecosystem, from mining, as in this chapter, to governance, and everything in between. Deadly Sin #1: Fear of 51% Attacks Deadly Sin #2: No Large-Scale Applications Deadly Sin #3: Account Insecurity Deadly Sin #4: 5 to 10 Second Blockchain Latency Deadly Sin #5: Proof of Work's Burning Billions Deadly Sin #6: Centralized Proof of Stake Deadly Sin #7: The Future is DAO