If you want to be a good product manager, continue to learn more about new and different ways customers will use your product. As much as you may design very specific tasks and use scenarios, customers will always find ways to use your product that you never intended.
WD-40 and baking soda are two other examples of essentially commodity products whose continued success has been driven by an understanding of customer needs and uses for the products. WD-40 introduced their Big Blast can when they saw that customers needed a way to distribute the same formula over a larger surface area more quickly and easily. Arm & Hammer had long recommended baking soda be used inside of refrigerators and freezers for removing odors. Open boxes could easily be spilled, though, which led to the creation of a special non-spill version designed for use in refrigerators and freezers. Arm & Hammer has further extended their line of products, making new products tailored for distinct but common uses.