(I work for a discount store that sells bulk birdseed that the customer scoops themselves. A customer approaches the counter with a bag that’s quite full but not tied.)

Me: “Hello, ma’am, how are you today?” (I start tying the bag shut so I can lift it on the counter to weigh without spilling.)

Customer: “No! Don’t!”

Me: “Excuse me?”

Customer: “Don’t tie a knot in it or it’ll weigh more!”

Me: “Ma’am. I’m sorry but, how’s that possible?”

Customer: “It’s a knot! They’re heavier!”