/Played
We avoid it like the plague. It is the cold hard truth, it is the exact number of hours spent playing WoW. For the uninitiated, /played is a command in World of Warcraf that breaks out the time played on your current character. Just type it in and hit 'enter' and bam! Days, Hours and Minutes. And it's the total time spent logged into the character, so unlike a job where in 31 day month you only end up working 23 days, WoW time is the actual time. So if you've got 31 days played it means you played for a solid month.
/played is a good tool to examine your play time, but not a very effective method of helping control your playtime. A lot of players feel a certain sense of shame when they type it in. If you're trying to cut back on WoW, try including /played into a macro for ability that you tend to use every so often, like a buff or ability with a few minute cooldown.
Try dividing out the time played over the number of days you've owned the game. Have you spent more time playing WoW than you have working? Sleeping? Knowing that you've wasted a lot of time playing is one thing; taking stock of all the things you could have done with that time is a step further. If this site's creator had worked for $5/hour for all of his time spent playing WoW, he'd have an extra $25,000 or so. The point is, if your hobby of gaming is taking up about as much time as work, you've probably got some priorities out of whack.
Don't fear the /played. Embrace it; use it as a catalyst for change.