1994 AFC Championship Steelers 13 vs Chargers 17
The infamous "Three More Yards" game. In spite of Pittsburgh's complete statistical dominance (415 yards to 226), the Steelers blow a 13-3 lead as San Diego hits two big plays and then stops the Steelers on 4th and goal from the 3 to win the game. One of the biggest heartbreakers in Steelers history and still the most disappointing loss of my lifetime.