College is stressful even without the classes: from moving away from your family to making new friends. So why would/should you even bother with challenging yourself while you're at college? Well, there's actually some good reasons to!
Remember when you worked the graveyard shift in high school and had to be up at 6 the next day to go to school? Having a job in college is almost like the job you had in high school, except it teaches you much more about time management skills - because college is grounded in the real world more than high school and is overall tougher.
Real World Experience
Realistically speaking, it's hard to get a part-time job in college for most people. But, that doesn't mean you can't challenge yourself in other ways - i.e. take a class that you know nothing about, or even declare a major that you think is super cool but also know little to nothing about. Because (let's face it), nothing in the real world is going to be clear-cut and simple all the time. There are going to be projects you take on that will require you to read up on a certain topic because you didn't learn it in college or don't remember too well.
This category could fall under "Real World Experience" but I've made it its own category instead. :) Anyway, the more you push yourself to do things that are outside of your comfort zone, the more qualified you are for any job or internship. For example, last semester I only had a Programming class that was part of my major and I applied for IT internships, but I was able to say that I challenge myself and constantly push my limits in my cover letters and resume. Because I've pushed myself by declaring a major where the only knowledge I had was what I taught myself, it gave me an edge and proved that I'm able to work through challenges (lo and behold I got an internship by doing this).
Get to Know Yourself Better
We all think that we know ourselves better than anyone, but we rarely ever want to challenge ourselves so we don't really know how we would react in high stress situations. Then again, putting yourself in these situations will help you get to know yourself better - and it will definitely help you find different ways to deal with stress and get through tough times.
In conclusion, I know it's not ideal to push yourself to extremes every day of your life (especially in college), but I think at times it's very necessary to challenge yourself in order to lead a good life and become the person you want to be.