For a very long time one of the hallmarks of my teaching has been over-preparation. I think it stems in part from my early experiences at the University of Chicago when my first few lectures went very poorly because I hadn’t tried out all of the things I was planning to talk about. Wanting to avoid repeating those embarrassing experiences, I learned to prepare, prepare, and prepare some more before each class. There were no examples that I discussed that I hadn’t thoroughly worked out beforehand, and my lecture notes tend to be extremely detailed. In some sense it was a success, since my classes have gone quite smoothly ever since.

But I know that there is a cost to over-preparation. Part of it is in the time it takes to get ready for classes, but that doesn’t bother me much. The cost that I’m less willing to tolerate has to do with spontaneity. It’s difficult to be spontaneous in the classroom when every example and every thought is hashed out beforehand. This sense of the spontaneous is something I admire, which may explain why I saved the T-shirt shown below from my high school hiking club. (Yes, I grew up in Southern Arizona. Where else would a high school have a hiking club?)


We were clearly a mellow bunch of students, but I think there is a good message there. Often the best things in life can’t be planned, only occurring when you follow whatever thing happens to be thrown in front of you.

It’s only now that I’m starting to be able to go with the flow in my classes. Yes, I still prepare for class, and my notes are as detailed as ever. But it’s more often the case now that I abandon the notes to go on a digression that comes out of some comments by my students or to expand on something that they have a question about. It helps that I mostly teach the Python classes now, and Python is the first programming language I’ve taught where the first thing that occurs to me to write is almost always exactly the right thing. Better spontaneity in my classes has made me happier as an instructor. So while I’ll never give up my preparation (at least I don’t think I will), it’s fun to run off the rails and see where the things I encounter take me.