I remember visiting colleges when I was younger and laughing at or feeling bad for the kids I found sleeping out in the public. They looked so miserable. Now that I am in college I can see why. When you're college, there are many things that are thrown your way. You have to worry about maintain good grades and a social life and sometimes it causes for one to not get enough rest. Yes, you're finally on your own but you don't fully known how good you are at time management until classes officially start.
I have had instances where I may not feel tired before class, but when class is about to end, I find myself dozing off slowly. I've realized that napping is actually one of the most beautiful things to experience in college. It keeps you alert and allows for your body to rejuvenate. So when next you visit a college and see a student sleeping, smile because you know they are putting their body and health first.