For many of us students, homework is not daily routine. We put it off until the very last minute, or perhaps we don't do it at all. Many of us are not motivated by overacheiving, but doing whatever we perceive to be the bare minimum. This, however, doesn't cut it for todays ambitious youth.
Underacheiving, as is explained above, leads to a sense of failure and worthlessness. These feelings are not conducive to future success. They cause you to feel hopeless, and without control of your life. Those who put no effort into their schooling, are unlikely to be satisfied with their education.
Maybe you're in a band, or maybe you have a girlfriend or boyfriend that makes you feel fulfilled. Either way, school is still a big part of your life. It's something you face multiple times a week, and it's very expensive. So it's bound to get you down if you are doing below what you think you're capable of.
Put in the time, and get your homework done. Do the assigned readings, and take notes. This is a key to feeling GOOD about yourself. Which is a key to acheiving your goals. Doing well in school is a very tangible acheivment, and it's just the acheivment you need to get into the mindset of success!