It al started back in 1995 when I was counting down for defending my PhD Thesis. Working on HPUX I modified XDaliclock, a C program for the X windows system to countdown in seconds to the moment supreme. Ever since that time I have been using a countdown timer whenever I am going to switch jobs. It has been modernized a little over time and is now a Java applet, but the principle is the same.
The countdown timer has become a tradition or even a ritual that I cannot do without. It is like a public statement that I am going to start something new very soon, which is so important that it is worth counting down to in seconds.