I would like to propose that there is a difference between being getting distracted and willingly interrupting your work.
Before I sit down to write, I prefer to know that nothing and nobody has any reason to interrupt me. This isn’t because I don’t want to be interrupted, but because I would rather interrupt myself. I will inevitably toddle away from my work, and I’d rather go willingly than be forcibly yanked away.
To better understand what I mean by ‘willingly interrupting your work,’ recall the last time you woke up. Did you wake up naturally as a result of your sleep cycle coming to an end, or were you jarred out of REM sleep by the grating WANK WANK WANK of an alarm? Did you feel rested after the wank alarm? No. You felt disoriented, confused, and annoyed. The wank alarm effect is what happens when you’re interrupted once you’ve gotten into the swing of your work. When some schlub wanders into your workspace and asks something of you it interrupts your train of thought and finding your stride again can be difficult.
When you choose to be distracted, though, you’re the one in control of when the break in thought occurs. Your focus will always peter out at some point and staring blankly at a blinking cursor for fifteen minutes won’t help you. Sometimes the words stop or your brain pan overheats. This isn’t a problem unique to you. In fact, it’s not even a problem. It can put a dent in your projected output, but it’s a natural occurrence.
My advice, as someone who’s absurdly far behind on his word count and satisfied with every word so far? Let it happen. Let your brain drift away a bit. It’s what it does.
Go for a walk. Take a long shower. Hell, play a video game. Pick up your favorite book and re-read your favorite parts. Maybe just space out. Go out for a drink and a bite, and no, don’t go to a coffee shop to get a mocha and sit in the corner. Go someplace with a counter and eat there, get a sandwich or a salad and just chat with people.
One of the hardest things about trying to finish a project is focusing on your output volume while at the same time retaining your grasp on the world outside your work. Forcing yourself through the pauses your brain wants so badly to take can keep your output level high, but you run the risk of exhausting your creative resources through over-extension and losing sight of the world beyond the page.