From neugierig.org:

A UNIX wizard hears cries of torment from his apprentice’s computer room where the apprentice is studying, and goes to investigate.

He finds the apprentice in obvious distress, nearly on the verge of tears. “What’s the problem?” he asks. “Why did you cry out?”

“It’s terrible using this system. I must use four editors each day to get my studies done, because not one of them does everything.”

The wizard nods sagely, and asks, “And what would you propose that will solve this obvious dilemma?”

The student thinks carefully for several minutes, and his face then lights up in delight. Excitedly, he says, “Well, it’s obvious. I will write the best editor ever. It will do everything that the existing four editors do, but do their jobs better, and faster. And because of my new editor, the world will be a better place.”

The wizard quickly raises his hand and smacks the apprentice on the side of his head. The wizard is old and frail, and the apprentice isn’t physically hurt, but is shocked by what has happened. He turns his head to face the wizard. “What have I done wrong?” he asks.

“Fool!” says the wizard. “Do you think I want to learn yet another editor?”

Immediately, the apprentice is enlightened.

Now, replace every occurrence of editor with communication medium. Each new communication medium will increase the number of ways people are able to contact you. Each one is one more way people have to interrupt you.