Sometimes the simple things are the things that irritate you the most, or are the most poorly implemented solutions to a simple problem. Take OSX's lack of a countdown timer - for me, a major pain in the butt. However, a simple dashboard widget does a stellar job of implementing this feature in an unobtrusive, elegant way. I give you (drum roll please): 3-2-1- no, that's not the countdown for the drum roll...that's the software's name!
Simple name, simple software - GREAT result. Kudos to the devs. Punch in a time, hit the green square and return to your desktop. When the timer runs out, dashboard takes focus and sounds a little (customisable) sound. Voila.
So why the hell would someone need a countdown timer? Simple - the next time you tell your wife, "I'll be about 10 minutes" then emerge from your office, with bloodshot eyes, sore hands, a crick in your neck and a bad odour several hours later, you'll remember this article and download the freaking software! :) Or in my case, avoid the situation in first place...honest.