Another big question for you

I feel as if this year i came into high school with a bit of an attitude. Why. Why ? Why because I feel as if my past three years of high school have been waisted doing homework and listening to lectures that are going to do nothing for me in the next five years . Lectures I really don't care about. So another big question why doesn't school teach things in life that people are going to need to know? Why do we spend four years of our life competing for grades and stressing out about shit that no one is really going to remember .