I spent the next couple of decades looking back on that year with regret and anger. First I was ashamed that I hadn’t been fully engaged. Then I gradually realized that to the extent that I wasn’t an active participant, that reflected poorly on him as well. He didn’t teach to the entirety of the class, just to the select few who fit his preferred student profile. I concluded that he did many of us a disservice and despite being very smart he was actually a poor teacher.