Disclaimer: These quotes are said by "real" professors in real lectures, heard by real students.
"Don't be crazy." -- apparently I say this a lot, but they are middle schoolers, they ARE crazy.
"Miss ***, I got jumped yesterday, and they asked for my Geometry homework, I had to give it to them." -- my very lovely, but horrible students
"Miss ***, if your mom is 52, then you can't be 42!" -- my lovely students with the look of terror
"Miss ***, my bird ate my homework and flew through the wall." -- my wonderful students
"Does this make any sense? (pondering) I don't know. I don't know and I don't care." -- my illusive math professor
"I don't care what it means." -- my same illusive math professor while proving a theory
"Is this interesting? (pondering) I am not sure. (pondering) No, I don't think it is." -- my illusive math prof again
"You may be off by a factor of 1020, but who cares?" -- only an astronomer would say that!!
"This is satisfying to me. I don't know how satisfied you are." -- yes, I had a lot of interesting professors
"I understand there is some confusion about one-sided tests... uh... please un-confuse yourself." -- my favorite illusive math prof
From other places:
"Did you say:'Billy, I love you?'" -- Hugh Grant as George Wade, "Two Weeks Notice"