Due to many factors (many of them personal) I'm keen on encouraging people to finish their studies. Especially Americans, who invested tens of thousands of dollars in their studies and are now paying high installments on their student loans, might find it a bit strange that people would enroll to a college without finishing it. But unfortunately in Slovenia that's quite common practice and especially software developers are often attracted to join companies before graduating with just a few exams left. On a recent job interview I was preaching again importance of finishing studies to a prospective candidate. Since I think this is a topic of broader interest I'm listing here reasons why I think it's important to finish your studies.
The first and in my opinion the most important reason is that one should finish what he or she has started. Finishing stuff is one the most important traits of successful people, since benefits of one's action can usually only be reaped at the end.
The second reason is probably the hardest to understand for young people since they feel so omnipotent and limitless in their options . But life is long and full of surprises, so sooner or later you'll find doors which will be shut just because you lack formal education. In many ways degree is a form of insurance policy. You might not understand its use now but you'll miss it dearly when you'll need it.
The third reason concerns your children that I hope you'll eventually have. I'm pretty certain you will want the best for your children including them having great education. I'm also certain that your children will be as rebellious as you are now yourself and it will be very hard to preach importance of education to them if you have unfinished studies yourself.
My grandfather made sure that all his three children graduated. I still remember vividly how proud he was when he was holding my engineering degree in his hands. So, if for no other reason, graduate to make people you hold dear happy.