I may have told this story before:
The schedule that we were expected to follow in graduate school at Illinois was long days Monday through Friday, a shorter day on Saturday (e.g., 9 a.m. to 4 p.m.), Sunday optional. One Fall Saturday in my first year, Penn State had a noon football game (vs. iowa, as I recall). Since I had to be home to watch it, I got to the lab at 6 a.m. and left at 11:30 a.m. As I’m waiting for the elevator to head home, my research advisor and an older graduate student appeared at the end of the hallway. I heard my research advisor ask the student, “Where in the hell is Keith going?” The student just shrugged his shoulders. I took the approach to beg for forgiveness rather than ask for permission.
Sure enough, on Monday morning, my research advisor asked me about Saturday. He was pissed, but I stood my ground. I told him that on Fall Saturdays, I would be watching Penn State and that I wasn’t going to apologize for it. He was still pissed and threw his arms in the air, but he let it go. He was a real dick my first year since he didn’t yet have tenure, but that was a rare disagreement between us that didn’t escalate.
I worked in his lab for three and a half years before getting my Ph.D. and never missed a Penn State football game during that time.