Common conflict(s) children have with their parents

The conflicts that I think children have with their parents is grades. Once children start to study for a quiz/test/exam for the next school day, parents just start to give them pressure about that "You have to get an 'A' for this test!" or "If you fail, I'm going to ground you!" etc., and children will start to worry, or maybe even give up! I believe that we should do our own best and not by our parent's force. This topic is oftenly brought up between parents and teenagers and it should stop occuring.