When you were a child, you might have seen bottles high on a shelf in your garage, out of your reach. "That's poison," your parent might have warned,...

When you were a child, you might have seen bottles high on a shelf in your garage, out of your reach. "That's poison," your parent might have warned, pointing to the container. "Don't touch." It nonetheless had some use. It was there for a reason. This example illustrates a principle: Items that can be misused often have a valid use, and vice versa. An average (e.g. mean, median, and mode) is not an exception; it can be useful, but if it is misused or misinterpreted it can be destructive.