这个问题一句话就可以回答了

为什么你没有也去，而只是在这里滔滔不绝。

如果你觉得这个回答太PERSONAL，不符合要求。换一个说法：为什么MOTHER TERESA 世界上只有一个。

附一段MOTHER TERESA的话：

People are often unreasonable, illogical and self-centered;　　
Forgive them anyway.　　
If you are kind, people may accuse you of selfish, ulterior motives;　　
Be kind anyway.　　
If you are successful, you will win some false friends 　　
And some true enemies;　　
Succeed anyway.　　
If you are honest and frank, people may cheat you;　　
Be honest and frank anyway.　　
What you spend years building,　　
Someone could destroy overnight;　　
Build anyway.　
If you find serenity and happiness, they may be jealous; 　　
Be happy anyway.　　
The good you do today, people will often forget tomorrow;　　
Be good anyway.　　
Give the world the best you have,　　
And it may never be enough;　　
Give the world the best you have anyway.　　
You see, in the final analysis, it is between you and God; 　　
It is never between you and them anyway.