设计中最难的部分是保持功能的简洁。
攻击我很厉害我也回敬得很厉害,攻击我很轻微我也回敬得很轻微。 
Enjoyment appears at the boundary between boredom and anxiety, when the challenges are just balanced with the person’s capacity to act.
The past is never dead. It's not even past.