Recognize the Distraction
It's not your fault that you get interrupted- distractions happen. Accept the fact that there's always someone who needs you with bad timing or an unfinished bag of Skinny Pop calling your name, just when you're hitting your stride. Say it or think it, "I'm in the middle of something important, I'll be back to you when I'm done." No further discussion, end of story. That's your game plan. Eliminate distractions by moving on and letting the interrupters know they have no power to control you. You are fully in charge.