For one, students should know how the world works. As an educated person, it's humiliating to seem uninformed and ignorant. Take myself as an example. When I was in high school, I was not fond of sciences and hoped to major in arts. I did see the point in attending those science classes and burning the midnight oil preparing for the examinations of physics and chemistry. However, I feel gratiful now that I was required to take those courses. Imagine how embarassed I would be if I did't even know the concepts of gravity, flash points or geomagnetic field.