Look at the way the top universities choose their students. High gpa in high school is almost essential for most students. In china, you will just need to great in one exam. Or in a year, one just need to do good in mid-, final exam. In the US, you have to be careful for all exams since 9th grade. They choose the ones that are good at exams.
I personally know a MD student, who has no common sense at all, but she is super good at exams, like many MD students. The only thing she cares in the class is whether that will be included in exams or not.
