Early in my marriage, my wife and I would infrequently haul out rolls of paper towel and window spray for the detestable work of washing windows. One of us worked on the outside and the other from in the house. Inevitably, one of us would tap in the window and point to a streak or spot that the other had missed. The trouble was that the person with the spot or streak couldn’t see it. We simply needed to trust each other’s eyes, follow the pointing finger, reapply the spray and wipe a bit longer. At times the work leads to laughter, sometimes not. Just this week I relearned the wisdom of this lesson again, twice: once in my classroom, once in another venue. Both reminded me of how much I need to continue learning. The classroom application came in a class in which I had been practicing a concept that I had been teaching the students for over two weeks and which would be on an up and coming test. Though the students coul...