(If any of these are not original, please blame it on my Commerce 335 professor,
Dr. Yair Wand. Otherwise, all humour can be attributed to him as the source.)

A physics professor was very strict about attendance, and despised
tardiness. Every student caught arriving to class late (especially those
interrupting his lecture) was quickly reprimanded in front of the whole class.
Students were quick to comment on the professors genetics. Well, one day a
student entered through the front doors of the lecture hall, while the prof was
writing notes on the chalkboard. The professor caught the student out of the
corner of his eye (this acute sense of peripheral vision, further supported the
rumours of his evolution), and turned to face the student. He demanded, What
do you think youre doing? Being a science student, one naturally thinks
quickly, so the student snapped up and replied, I came down from the back to
get a better look at the board. The prof smiled.

Back in those days, it was required that in order for a student to receive
credit for a particular course, a card (listing of his/her courses) had to be
signed by the instructor/lecturer. It was, at the time, policy that students
attend their courses. But depending on the size of the class, it was often
quite possible to receive credit, even after not attending the class regularly.
Not so, with this physics professor…if he didnt recognize you, you would
have to repeat the course (& attend!). On one occasion, a student handed his
card to be signed. The professor looked at the name, then at the student, and
said, Ive never seen you in my class, and handed back the card. Now being a
science student, he naturally thought quickly, and proceeded to the end of the
line. When he was at the front again, he handed his card to the prof. The
prof looked at the name, then at the student, and said, You look familiar.
OK, and signed the card.