I was a kinesiology major in college, which is exercise science. Then, I was either going to get my Ph.D. or go to medical school, but I was kind of burned out after school.
I almost stopped teaching entirely. The worst thing for me is contact with students. I like universities without students. And I especially hate American students. They think you owe them something. They come to you ... Office hours!
I feel that I've had enough theoretical speculation to last me a lifetime.
I spent every night until four in the morning on my dissertation, until I came to the point when I could not write another word, not even the next letter. I went to bed. Eight o'clock the next morning I was up writing again.
One had to cram all this stuff into one's mind for the examinations, whether one liked it or not. This coercion had such a deterring effect on me that, after I had passed the final examination, I found the consideration of any scientific problems distasteful to me for an entire year.
Somewhere in university, I realized that I hadn't been to classes in months, and I'd get tired to the point of narcolepsy doing anything other than some form of performing, directing, writing, or acting.
Professors go batty too, perhaps more often than other people, although owing to their profession, their madness is less often remarked.