We all know that a wandering mind can lead to disasterous results at the hobby bench, but the flip side of that is being too focused on the task at hand. As when you are drilling out the gridwork in a 1/700 plastic seaplane launching rail with your No. 80 bit, and can't figure out why it's taking so long to do each hole.
Until you stop long enough to take the bit out and actually look at the tip, only then realizing that you broke it off about 10 holes ago ...