Today, a dissatisfied customer would probably leave a one-star review, send an email complaint, or post on social media. In fact, almost 4,000 years ago, one Mesopotamian client had a much older way of voicing his displeasure: carving a complaint on a clay tablet.

Today, a dissatisfied customer would probably leave a one-star review, send an email complaint, or post on social media. In fact, almost 4,000 years ago, one Mesopotamian client…

World's first angry customer: A 4,000-year-old clay tablet is believed to record the world's oldest known customer complaint from ancient Mesopotamia. A customer named Nanni…