To understand how important good management is, think about mistakes like these: Mistake #1. A high-level bank manager reduces a marketing manager to tears by angrily criticizing her in front of others for a mistake that wasn’t hers. Mistake #2. Guidant Corporation, which makes cardiovascular medical products, waited for 3 years, forty-five device failures, 77 percent of which were already implanted in patients. Patients were told that if they heard a beeping noise, their defibrillator was malfunctioning and they should see their doctor or go to an emergency room.