How did the Potvin Sucks Chant begin?
The Hit
February 25th, 1979 at Madison Square Garden. Rangers vs. Islanders.

During the game, Islanders captain Denis Potvin laid a brutal check on Rangers center Ulf Nilsson. According to Nilsson it was a clean hit, but his skate got caught in a rut in the ice. The result was a broken ankle that sidelined Nilsson for months.
The Chant
That night, a chant was born. Every time Potvin touched the puck, the crowd shouted "POTVIN SUCKS!" But that night was only the beginning. The now legendary chant would be heard again each time the Islanders came to town. It then took on a life of its own. The chant could be heard at every Rangers home game no matter who the visiting team. When the organist played "Let's Go Band" , a sports arena standard, Rangers fans would take the last three notes and turn it into "Potvin Sucks!" It has even spread to other hockey arenas and even a Phish concert at Madison Square Garden in 2019.
The Whistle
Eventually the organ tune was retired because Garden officials didn't want to encourage "crude" behavior. But of course that didn't stop the fans. The organ was replaced by loud whistling coming down from the blue seats. At the end of the whistling, the crowd takes its cue: POTVIN SUCKS!
The chant continues to this day, 43+ years later, with the next generation of hockey fans chanting "Potvin Sucks" and many not knowing why.