We don't realize how nice a summer break is until it's ever so rudely taken away from us, whether it be from work, classes, etc. While some 20-somethings are able to take the time to travel and vacation in between semesters, many of us aren't so lucky. Days off are few and far between, and some people work 2-3 jobs in order to pay for school. Some of us take a class or two, or four, in order to catch up or stay ahead credit wise, and course work really takes a toll on your free time.
As July is vastly approaching, summer is almost half way over, and then the college kid grind welcomes itself back into our lives. Busy work schedules transition to busy class schedules (sometimes they remain) and the break never comes. And while it may seem exhausting and intense now, it'll all be worth it in the long run.
Extra classes are a good idea when looking at the big picture, but as you take them they drag. I've only had to take a few, but I know my friends tackle 12 credit sessions while working, only to get a few weeks break and start back up in the fall. And it's hard. If you think waking up and walking to class is hard on a spring day, imagine having to do 2 hours of Spanish homework when it's a beautiful summer day and everyone else is out having fun, or being stuck at work in the same situation + loads of school work waiting for you at home.
Now back to the being worth it part: it will be. Right now the 30-60 hour work weeks seem grueling, the school work piles up and seems like it will never be finished. It will. Although it seems like you're missing out on life, you're making better decisions than those who choose to blow off working for a fun summer, and your resume will build and your success will soar (once the paychecks run out, it's a different story).
So whatever kind of summer you have, one full of classes, or of long work days, or just some fun in the sun, enjoy it. The days of laying out and going out 24/7 may be over, but your college age days are numbered.