His famous WrestleMania VIII match with Bret Hart, where, after teasing a heel turn (and wielding a ring bell at that!) he just couldn't bring himself to screw over his old friend. Bret ultimately wins, but the two embrace afterward in a very rare show of respect from Piper.
Piper was voted to be Ric Flair's partner at Cyber Sunday 2006, but had to be withdrawn from storylines shortly afterward when it was discovered that he had cancer. Piper made a full recovery and credits the fans' vote as being what saved his life.