Why punctuality became a virtue

We all know people who are always late. Maybe you're one of them. The tardy gets a bad rap. But they aren't all self-centred, says University of Texas time expert Dawna Ballard. Some of them may be time blind. Others simply can't pull themselves away from people they value. Understanding what's behind our time personalities might help us get along better -- and rethink when and why we obey the dictates of the clock.