Why is calculus so hard?

Why do so many students struggle with calculus? Is it the complexity of the concepts, or the abstract nature of the math? Perhaps it's the steep learning curve, or the difficulty in applying the theories to real-world problems. Whatever the reason, calculus seems to be a common hurdle for those pursuing advanced mathematics and science. But why is that? What makes it so challenging for some, and yet fascinating and rewarding for others? Could it be the problem-solving skills it demands, or the satisfaction of mastering a difficult subject? Let's delve deeper into the world of calculus and uncover the reasons why it's so hard for some, and yet so rewarding for many.