My first year in graduate school, I took a course in structural mechanics taught by Bob Eubanks, a remarkable man who combined highly theoretical research with a very down-to-earth personality. He was powerfully built, bald with a little moustache, and had a habit of making noises as he breathed that combined humming, growling, and snorting. The impression he gave was that of a bull.

During the final exam, he sat at a desk at the front of the class, reading the newspaper and occasionally looking out at us. About an hour into the test, he must have seen something in our faces or our frantic scribbling that bothered him, because he got up and walked around the room, stopping behind each of us and giving a little grunt as he looked at our test papers. This was not a confidence-builder.

When his tour was complete, he returned to the front desk. “Gentlemen,” he said, “if I might make a crude suggestion… If sex is a pain in the ass, you’re doing something wrong.”

He went back to his newspaper. We all looked at each other and then at our test papers. Most of us decided to put our pencils down and rethink whatever problem we were doing. Thirty years later, when I find myself struggling with a problem of any sort, I remember Bob Eubanks’ advice, put my metaphorical pencil down, and try to rethink the problem.