一个好的模型应该在复杂性和准确性之间取得平衡，捕捉基本动态而不过度拟合。
Optimism is a learned skill. Once you learn it, you can improve your life in every way.
"世界是一个舞台，但演员选得很糟糕。"
The laws that forbid the carrying of arms are laws of such a nature. They disarm only those who are neither inclined nor determined to commit crimes.... Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man.