Riddle: Two twin sisters walk into a restaurant and order a hamburger and a coke with extra ice each. One of the sisters has to leave early to meet her boyfriend and rushes out of the restaurant. The other sister stays there and finishes her meal, reads a book, and becomes friends with the waiter. When she leaves, she drops dead at the door. She had been poisoned, yet the other sister was fine. How is this possible?
Answer: The ice was frozen poison, and the first sister left before it melted into her drink.