Playing chess is a life lesson in concentration
Once one has learned how to concentrate, the next thing to learn is to be able to concentrate on the right thing.<p>Chess taught me to concentrate, but I've always had trouble concentrating on what I should be concentrating on, and instead wasted too much time concentrating on chess and other diversions.<p>The real trick is being able to focus on something even when it gets frustrating, painful, or boring, and being able to do this for extended periods of time.  Then the world is your oyster.