I have wondered the same myself. My solution is simply practice - making a planned, conscious effort to get back to my work whenever I'm distracted. At first,

I have wondered the same myself. My solution is simply practice - making a planned, conscious effort to get back to my work whenever I'm distracted. At first, I could lose up to half an hour distracted before realizing that I'm distracted and go back to work. But after a while, the time-to-realize got smaller and smaller. Once you get to a small enough interrupt window, it'e effectively the same as not being interrupted at all.