Wayne Gretzky to the Kings (1988)

Edmonton traded the greatest hockey player ever for $15 million and four role players, sparking national grief in Canada as Gretzky left for Los Angeles. He went on to win four more MVP awards with the Kings, while the Oilers never won another Cup — a stark contrast to their four titles with him. This deal is cheaper than the average superstar trade in terms of return, as Edmonton received just 50% of his on-ice value. It ranks below #1 in total curse duration but above #4 in raw emotional cost, breaking millions of hearts.