I was one of those types who had a lot of problems with math in primary school because the style of "here are 150 problems for your homework tonight, just like every other night" didn't work with my learning style at all. It took me a long time to overcome this, and while I can't really give an example of this with calculus, I've run into this with other similarly "advanced" mathematical branches such as combinatorics, which comes up in all sorts of CS contexts dealing with trees or similar data structures.