There are a lot of situations in life when people have to tune out distractions. Think about that college or pro ball player, standing on the free-throw line with the game tied, the win or loss up to him. Fans from both sides are screaming and stamping. He's got to learn how to tune out these distractions and focus on the job at hand. If he can't learn how to do that, he won't last. Ditto with, say, a concert pianist. No one may be shouting or stamping at her recital, but hundreds of eyes are on her (not to mention ears), and an audience's intent concentration on you and you alone can be just as nerve-wracking.
But like the ball player, the concert pianist has to tune the audience out and concentrate. You, too, can learn how to ignore or avoid distractions so you can better focus on your work. Business experts have a host of ideas on how to do so, from working on the tasks that require the most concentration at specific times (e.g., before the gum-snapper gets to the office) to turning off the sound alerts on your email to prioritizing tasks on a to-do list [sources: Smith, Orenstein]. You'll probably never be able to tune out every office distraction, but you should be able to diminish the extent that they affect you.