Customer: “Hi, my laser printer has a flashing light that say ‘change toner’. What must I do to fix that?”

Me: “Well, sir, your toner cartridge is empty. You just need to replace it.”

Customer: “What is a toner?”

Me: “It’s the ink that your printer need to print on the paper.”

Customer: “What! How come it needs ink? It’s a laser printer! Doesn’t the laser directly write on the paper without ink?”