This Is The Last (Day) Straw

(I work in customer services for a small finance company. We get a lot of basic queries from customers about their accounts.)

Me: *answers phone* “Good morning, [Company]. [My Name] speaking. How may I help you?”

Customer: “Yes, I want to know why you took my Direct Debit earlier than usual? It made me go overdrawn!”

Me: “I’m sorry about that, sir; let me just take a look at your account.” *pulls up account info* “It looks like your Direct Debits are set up to go on the last day of every month.”

Customer: “Yes, the 31st! In September you took it early!”

Me: “…that’s because September only has 30 days.”

(Later:)

Coworker: *after I’ve told her the story* “God help us when he gets to February.”