One semester when my brother, Peter, attended the University of Minnesota in Minneapolis, an art-student friend of his asked if he could paint Peter’s portrait for a class assignment. Peter agreed, and the art student painted and submitted the portrait, only to receive a C minus.

The art student approached the professor to ask why the grade was so poor. The teacher told him that the proportions in the painting were incorrect.

“The head is too big,” the professor explained. “The shoulders are too wide, and the feet are enormous.”

The next day, the art student brought Peter to see the professor. He took one look at my brother and said, “Okay, A minus.”