(Reuters) To anger a banker, just say his bank will drop the ball when it comes to handling the so-called Millennium bug. Making fun of "Y2K" fears, KIA Motors America and Polaroid Corp. have crafted TV commercials that suggest people's deposits might be in danger when the calendar changes to the year 2000. But bankers don't find it funny at all. The clash between the American Bankers Association and the companies throws light on the inner workings of the advertising world, where humor and exaggeration are often used to capture the attention of audiences.