When a retired New York woman left her $424,000 cashier’s check at a local pizzeria, she said she felt her “world just collapsed." That is, until an unlikely hero came to save the day: the very waiter she burned with no tip and a sassy note. After looking at a condo she hoped to buy, Karen Vinacour, her daughter and a real estate broker went to the historic Patsy’s Pizzeria in Manhattan to grab a slice of their signature brick-oven pizza — the same pizza enjoyed by the likes of Frank Sinatra, Al Pacino and even Justin Bieber. Tucked in...