"never learn something not useful"

many poeple may ask such a question when they were in school, or when they were studying:

"is the cubic root useful?"

"is the log function useful?"

"what is the use of those?"

As a "angry" teacher, i will reply them like this:

"Are you useful? No, you are not useful now. you need your parents, you even cannot take care well yourself. you did not make any contribution to the society! so, you should die."

Well, you can see the point is about the time. many things are not useful when you learn it, but it does not mean it is not useful at all. you never know how and where you use it one day.

As a beinger, you have right to ask the question of useful, coz you know nothing about it and, i presume, you like to use what you learn. However, when you ask such a question, just because you want to escape from the learning of challege, then, it is no more about the usefulness of the thing, but the usefulness of yourselve.

they are not useful, as long as you are not useful.

a great people said," i never learn something not useful." he means, he can use everything his learned, and then make nothing not useful.

some guys may further say, "not everyone needs to be great". well if some "human" had this thinking, he is not human at all, "it" is a single cell organizm with "human body", i.e. it is a lower-life-form of alian, which can be wiped out from this earth without any complain.

pursue, you may fail

stay, you must fail

therefore, i still teach, coz i believe they may useful some day.