Carolyn Hax writes an advice column. She recently published a letter from a woman who was allergic to shellfish. In her letter, the woman explained that she had been dating a man for a few months, and early in the relationship had informed him and his family of her allergy. The man’s mother did not believe her, however. The woman went on to write that recently she had dinner at the home of her future mother-in-law, and shortly after eating became ill and had to be rushed to the hospital. It turned out that her future mother-in-law had cooked the meat in the same oil she had cooked clams to prove to her son that the woman’s claim of a shellfish allergy was a lie.