One thing I learned about myself at my defense is that I absolutely cannot do any kind of math on the spot. At all.
There are many regressions in my thesis, and Dr. X was suspicious of some of my r^2 values. He asked, if the r^2 is 0.41, what is the r? Um, um, um, ...0.2? Embarrassing. He also asked me the difference between standard error and standard deviation. This is something I know, of course, and of course I mixed it up in my answer. To top it all off, Research Adviser noticed an error in some calculations she had me add at the last minute. There are two ways to make the calculations, both valid, but she thought that I had made the calculation one way and written that I did it the other way. So she asked me to describe the algebra for solving the equation the way I said I did it. It was like she asked me to give my answer in Russian. So, thinking it would help me, she asked me to solve the equation on the white board. I got all flustered and bumbled through it. I tried to diffuse my humiliation by joking that this was my fifth-grade nightmare. That got a laugh and got them to help me through it.
At several points when I felt things were getting unnecessarily serious, I joked around a little bit or said things that were a a little lighthearted. I'm not sure if that annoyed the committee or relaxed them, but it definitely relaxed me. I figured I've had lots of successful discussions with scientists at meetings or during visits, and I felt like I would do my best if I pretended that this was like any other conversation about my work.
Three hours and 15 minutes after it started, Academic Adviser asked if there were any more questions, and then asked me to leave the room. They deliberated for over 20 min(!) during which time I was in my office around the corner with EGM. According to Research Adviser, the deliberations weren't about whether I passed, but about what kind of revisions I should make. Academic Adviser finally came to get me and after we were back in the room told me that the decision to pass me was unanimous. As he shook my hand, I asked if there were any major revisions. He said there were just minor ones that we would discuss later. The others shook my hand, congratulated me, and then went off to pee. Neither Research Adviser nor I are hugging types, but when I went to shake her hand she said I needed a hug instead. Seriously people, I rarely cry , but I misted over when I hugged her. It was awesome.
After that, we joined my labmates for champagne. Then my two advisers and most of Academic Adviser's lab went to dinner at a decent restaurant nearby, which was a lot of fun.
The following Monday my (non-university) office was covered with mini Twix's and decorated with congratulatory paraphernalia. They even had a surprise pizza lunch for me, complete with brownies baked with Twix bits -- Awesome Technician's best stab at a
Twix cake. It was terrific. It reinforced my conviction that I have some really wonderful colleagues and made me feel really special. Research Adviser gave me a copy of a high quality text book that is considered the bible of our field - a gift I highly value.
I met with Academic Adviser the next week to get the list of required revisions. Fortunately, they're pretty minor. Basically, he wanted me to ensure that all the numbers were correct but told me not to spend my time changing the text. Rather, he wants me to focus on preparing my chapters for publication, and to incorporate the committee's comments in the papers, not in the thesis.
Before the defense, I promised myself no regrets. Based on positive feedback from my committee before the defense, I was pretty sure I'd pass. Still, I knew I'd flub some questions or wish I had answered some differently, but I think that's par for the course. You can't beat down a barrage of questions for several hours without missing some. So I decided that as long as I passed without huge conditions, I'd allow myself to be happy with my performance and not beat myself up over any mistakes.
So, between the challenging questions at the defense, the champagne toast, the celebratory dinner, the surprise pizza lunch, and the relatively minor required revisions, I say my defense was pretty climactic. I'm grateful to everyone who had any part in it and I'm so glad it's behind me.