Well, I can tell you this. My parents demanded the absolute highest standard of grades, and I rarely got so much as a 'good job' for living up to it. I felt that they were lying to me about the importance of grades, because the only time they seemed to be important to them was when I wasn't doing well. Parents are quick to punish kids for bad grades, but when you don't reward for the good ones, it sends mixed messages about the importance of these grades.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell