I was in the American school system up until HS and then moved to France. The _way_ stricter grading compared to what I had in the US was very hard to get used to.
One thing that I did witness while studying for the engineering school exams (which is a whole two year affair) was seeing a lot of people who were very used to being the top of their class and getting good grades flame out, because they had already been working super hard in high school to keep their grades up.
I think there's a good chunk of "straight A students" who might struggle with the hit to their ego in that environment. But it was helpful and humbling to me.