1. If you are applying for graduate schools, you actually need to take hard courses anyway.
2. I personally think difficult courses are a lot more fun than easy courses. For example, I went to a first lecture of introductory microeconomics class, and the instructor started talking how to find a slope of a line from looking at a graph (no, not the graph as in graph theory, but I mean the one with the x-axis and the y-axis, you know? You basically have a curve, and you were asked to find the secant line of two points!). I dropped that class as soon as I got to a computer station. On the other hand, I've taken a fair amount of hard math classes (probably easy for some), and while I found them difficult and I didn't always get A's, I actually felt like I learned a lot from these courses, and overall they were fun experiences.
Conclusion: Some people think I'm a masochist. I'd like to call myself a mathochist.