Tracy: Countdown To What?

We've all seen them, the calendars with the big x's, marking off the days. What exactly is the goal of that countdown? Are you marking off the days till your demise, the end of the world, your last hurrah? It seems a bit morbid to me. Why not celebrate your life and your days and your accomplishments? Those big x's scare me. If you want to put an "x" somewhere, play a game of tic-tac-toe...