The company by which I was employed at the time had technical support personnel at several sites around the country to keep computers and programming working correctly. One day I got a call from one of the field people saying that a program that I'd recently "improved" wasn't working correctly if the current date was in January or February. Without pause for thought, I responded: "So, don't use the program in January or February. What's the problem?"
There was a long silence from the other end of the line...