... why we should try our best.
I believe that parents should expect us to do the best we can, because if you don't try to do your best, you will kick yourself for not listening to them. Do you really believe that it is a goo idea not to listen to someone who has done it all before. You are doing yourself a favour by listening to them as you will just have come out of your GCSE's, thinking about the fog of blankness that passed through your head trying to remember what a quadratic equation is.
My parents have always put an immense amount of work in trying to get me to the best of my ability. Many of you have been forced into a tutoring class by your parents and at the time hated them for it. If you put down your phones and Xbox controllers, then you will be doing yourself and your parents a kindness.
If your parents are not enthusiastic, then you should remind them that if they help you, they will be paid back for their efforts with a fountain of A*s.
So in conclusion, your parents have worked hard with you, so you should give them back your hard work as well, otherwise they will have wasted your time as well as theirs