I supported myself through the first term of grad school by being a TA, and this is what it felt like. This comic started a long running theme of featuring pi/2. I did it because it seemed to me in problem sets that the answer was always conveniently something simple like that, probably because the instructor started with the answer and worked backwards to get the question.
I've been a TA for 2 years, Controls and Mechatronics Laboratories. I can say that, without question, sometimes I would explain something or try to figure out a problem compiling code, And even sometimes copy the code that worked when I performed the lab to make sure everything was working, and if it still wouldn't work, my answer was always "Don't worry about it, I'll talk to the grader." :-P