(The professor in this graduate-level course has just incorrectly written the general form of a 2×2 matrix inverse on the board.)

Student: “The inverse is wrong.”

(The professor tries to explain why he used the matrix inverse here.)

Student: “No, the matrix. It has the wrong entries.”

Professor: “Oh, that is embarrassing. Maybe I’ll just remove my pants to distract you.”

(He did not, thankfully.)

(I am in psychology class at a community college.)

Professor: “What’s the one substance that will make you act stupider than any other substance on earth?”

Male Student: “Testosterone.”

Professor: “Well… yes, but I was talking about alcohol.”

(I’m female and one of four students in an advanced math class. The class is held last period, and since there’s only a small number of students we often finish work early. I also happen to be on my period.)

Me: “Hey, Mr. [Teacher], can I go to the bathroom?”

Teacher: “Well… I’m not really supposed to let you go during class.”

(Since it’s last period and I have already finished all of my work, there’s no reason not to let me go. However, as this teacher is rather new, I decide to try something different.)

Me: “Do I need to show you?”

(I dig around in my backpack and grab a pad, then hold it up in front of him. The teacher turns white while the other students laugh.)

Teacher: “All right… you can go.”

(As everyone is still giggling, I go to the bathroom. I return about five minutes later.)

Teacher: “Next time you can just say it’s an emergency.”

Me: “But it wasn’t an emergency per se.”

(My teacher puts his head down on his desk. One of the other students, a girl, speaks up.)

Student: “Mr. [Teacher], are you scarred now?”

Teacher: “Yes!”

(In my science class we have a weekly report due about a science-related article we read during the week. One week, I do mine on an article I read about decreasing butterfly numbers. This is the note I get back from my teacher stapled to the report.)

Note: “This is sad because I like butterflies.”

(My brother is talking about how his Korean teacher’s questions have been getting stranger since the teacher’s son was born earlier in the year.)

Brother: “They’re getting really weird lately.”

Mum: “Well, he’s probably tired!”

Brother: “But seriously, [Friend In The Same Class] showed me her homework yesterday and asked, “Does this really mean ‘I bought my girlfriend in Amsterdam’?””

Mum: “Did it?”

Brother: “I had a look and told her, “No. It means ‘I bought ‘a‘ girlfriend in Amsterdam’.”