Your need to feel needed and useful gives you the drive to work tirelessly to meet your goals or the goals of others. This is an admirable quality intensely favored by our modern society, but step back and take a realistic look at what it's doing to your body. Are you putting off exercise in order to work more? Are you skipping meals or eating poorly due to the work schedule you keep? Make your work ethic a real virtue and remind yourself when it's time to quit!