I had the privilege of being an undergrad in Jeff’s class in the late 90s. IIRC, it was his first year teaching. On the last day of class he received a standing ovation. The average grade on the final exam was ~50%. And yet he received a standing ovation. He’s that good.

I had Jeff his first semester at UIUC. He received a standing ovation the last day of class. He's _that_ good.