When Joanne Wang went out for dinner to celebrate her 24th birthday, she expected to split the meal evenly. She was spending the evening with a new friend, so she figured they would each pay for their own order. When her friend decided to bring her boyfriend along at the last minute, Joanne didn’t think it would complicate the economics of the dinner.
Instead, Joanne said, the new friend and the boyfriend ordered oysters and calamari — appetizers Joanne couldn’t share because of her shellfish allergy. They also had two more drinks than she had each. At the end of the night, Joanne’s new friend put down her card. Imagine Joanne’s shock when…
