When I was in High-school I took a class in physics. One day the students were given a lab experiment to do and then sent over to the lab to work on it. None of us really understood what the experiment was or how to make it work. So we just sort of stood around mumbling and getting confused. The teacher was sitting on the other side of the room doing some work at his desk, and without looking up he shouted over at us, "If I didn't know what was going on, I think I'd ask somebody who does." One of the students went over to the teacher and asked if the teacher could explain the experiment again. He did, and we completed the lab.
I've long since forgotten what the experiment was or what it was intended to teach, but I will never forget what the teacher said. If there is something I don't understand, I need to ask someone who knows.