More valuable knowledge comes from learning outside the classroom. Anyone can memorize countless, meaningless facts and do well on a test. The real challenge is the actual learning of material and keeping that knowledge for the rest of your life. No one becomes a good reporter from a class, they do it in the field. Doctors get their real training in the hospitals.
Teachers learn to teach in their own classrooms.
Most people have heard that Albert Einstein was a mediocre student in high school and college. My advice to my fellow students is to give up on the ever-elusive 4.0 and concentrate on the knowledge that is right there in front of you. Focus on the things that you find most important and most interesting. Obtaining actual knowledge is far more satisfying then getting an A because you stayed up all night memorizing some book. Don't let your professors fool you into thinking that they are teaching you something or that they can even teach well at all.