I hate to break it to you, but once you graduate and enter the job market, life is still lived as an obligation to "9 to 5", in other words, 8 hours of work. Maybe joining some groups at school (music, or one of the social groups) would make school more fun.
The more serious you take your education, no matter what grade you are in, the better prepared you will be for the job world. Graduating near the top of your class always helps when you start your career. Not only will you get a better paying job but it increases the chance of you getting a job you will enjoy.
Try to do something that makes learning fun. Have you tried reading outside material on some of your classes? You not only learn more that way but it gives you a chance to challenge your teacher with your outside the classroom knowledge (and this is fun if you do it in a polite way)