They don’t really think you’re lying, though - they just want to get something out of you, and telling you you’re lying makes you the bad guy more likely to give them what they want.

Why are customers always convinced people are lying to them? They have only one cup size, they aren’ trying to trick you for the fun of it. I one time had a customer, when I worked at the convenience store, swear up and down they paid for a money order with a credit card there just recently. The damn computers didn’t…