Also, the time of focus loss grows highly super-linearly with the distracting delay time. One second could be imperceptible, once you get used to it, 15 seconds is enough to get distracted by looking at something else, like checking IM / email and spending 2-3 minutes on returning to the full focus, and 2 minutes is enough to go for a coffee / reddit / YouTube, and a potential loss of an hour of focus time.
Also, the time of focus loss grows highly super-linearly with the distracting delay time. One second could be imperceptible, once you get used to it, 15 seconds is enough to get distracted by looking at something else, like checking IM / email and spending 2-3 minutes on returning to the full focus, and 2 minutes is enough to go for a coffee / reddit / YouTube, and a potential loss of an hour of focus time.