Why is english important?

It might appear to be a trend in which people nowadays have come to know the importance of grasping or mastering English as the international language. Undoubtedly, it will provide you worldwide opportunities for you to further studies or apply for a job position. Think about it, if an employer were to pick among two potential and talented people to be the company's right hand, it goes without saying that the one with more eloquence and understanding of English as second language will stand a higher chance to be employed. Besides, English is the language of knowledge as well since most technology is invented by the Western countries and there's a number of journals or books that contain knowledge of science, medicine or art since time immemorial which will be truly enlightening if you know how to read it and enrich your mind. I would say one will lag behind of the world if you do not master it, though I am not highly discouraging the learning of other languages but when it comes to English, you gotta get to know a thing or two for your own advantages.

because when people ask you “go [词语过滤-#] yourself.” politely.

And you understand his meaning.

I mean totally.

It's the international language. The one and only answer.
Because if you're fluent in English, you basically can go anywhere because there must be someone understand English, even just a tiny bit.

Fully agree, if you do not understand english you were 50% behind the world battle. In fact,  english was not as difficult as most people think if you really wanted to improve yourself.

bcos english is most common language which is used around the world in every field.

不过身为华人必须以传承华文于下一代为基本任务，并努力将华文发扬并与英语平起平坐甚至超越其地位。

English is international language. However, you may want to know that Spanish is getting more important.