童话故事比真实更真实：不是因为它们告诉我们龙存在，而是因为它们告诉我们龙是可以被打败的。

The defining characteristic of pessimists is that they tend to believe bad events will last a long time, will undermine everything they do, and are their own fault.

I would not dare to say that there is a direct relation between mathematics and madness, but there is no doubt that great mathematicians suffer from maniacal characteristics.