The enormous pop DDP got when he debuted in the WWF. Bear in mind, the gimmick he was given was that of a creepy stalker, with WWF hoping to bury him (because, you know, they just had to show that WWF veterans were so muchbetter than former WCW wrestlers). It says a lot about the man that he managed to remain likable despite that. The crowd goes from booing him when masked, to immediately cheering as soon as they recognize him. Then he cuts a promo that masterfully frames the entire stalking plot as his way of getting in the Undertaker's head because he wants to take on the Deadman to begin his ascension to the top of the WWF. And sure, he gets some boos for the moments where he's particularly snide and mocking towards Taker, but otherwise people are cheering because they want to see DDP vs. Undertaker.
His 2012 reappearance after Heath Slater, who had been getting squashed by legends/veterans for weeks, actually won a match by defeating Doink the Clown. His music hit, the half of the crowd that was old enough to remember him flipped their lids, and he came down to the ring and extended a hand of congratulations to Slater, who shook it. BANG! Cue Diamond Cutter.
Just the work he has been doing with Jake The Snake and Scott Hall. Both were so sick they were as good as dead. He took them both into his place, trained them, took care of them, even put up the Indie Gogo projects to pay for their surgeries. Two of the saddest drug-addiction stories in pro-wrestling, and he made them both turn a new page.
Let's put it this way: You know Jake's stunning return to WWE on Old School Raw on January 6, 2014? That doesn't happen without DDP.
Any time he hit the Diamond Cutter, which always got massive pops. Lots of wrestlers tend to brag that their finishers are universal, and that they can turn anything into a reversal to their move. Well, DDP's Diamond Cutter was a move that didn't just talk the talk, it walked the walk. He once boasted he could counter moves a different way every week for an entire year…and you believed him.
His return at the 2015 Royal Rumble, where he hit everybody in the ring with the Diamond Cutter, even Bray Wyatt.