#1 The entire Shawn Michaels vs Bret Hart feud
Back in the mid-90s, Shawn Michaels and Bret Hart were two of the biggest Superstars in WWE. Both were excellent wrestlers and carried the company on their backs for the better part of the 90s. Hart and Michaels fought over the WWE title on various occasions, most notably at WrestleMania 12.
The Heartbreak Kid came out victorious in the end, winning the WWE title in the process. A rematch was scheduled for next year's WrestleMania, but Michaels "losing his smile" sent the plans down the drain. Hart faced Stone Cold Steve Austin instead, in one of the greatest matches in WrestleMania history.
Corey Graves deleted his Tweet! More details HERE.
Michaels and Hart had major real-life issues with each other, and it showed whenever these two Superstars faced each other on TV. Michaels and Hart weren't fond of each other and this real-life feud made sure that their on-screen rivalry would become one of the most memorable feuds of all time.
The insulting promos the two cut on each other were a reflection of what they actually felt about each other in real life. Hart and Michaels would settle their differences years later, and WWE went on to produce a DVD chronicling their real-life issues as well as their on-screen rivalry.