When you repeatedly ask students to stop leaving their things in the middle of the classroom floor, and then you step on one of their charger blocks and sprain an ankle. Cool.
Student 1: "What is this world coming to when people don't know the difference between extortion and blackmail?"
Me: "That's what you call a first-world problem."
Student 2: "Ya know what else is a first-world problem? Communism."