Winning the World title after a full decade of being a mid-carder and holding it longer than 24 hours.
It says a lot about the fans' respect for Kane that he won by cashing in his Money-In-The-Bank contract on the very popular Rey Mysterio, Jr.....and STILL got a strong positive reaction for his title victory.
Also take note that this happened in 2010; meaning that this is an inversion of Thirteen Is Unlucky. Kane truly deserved that championship after going through all those storylines.
Retaining the Tag titles, by himself, in a four team TLC match. Also, winning the ECW title in less than thirty seconds.
The fact that he might be the only wrestler to have defeated The Undertaker in three consecutive Pay-Per-Views is one as well.
The return of his mask at the 2011 Slammy Awards.
When he starts doing promos, they turn into awesomeness. There's the one where he vows vengeance on whomever put his brother into a coma (Even though it was later revealed that he did it). Then there's the one in January 2012 where he's trying to get John Cena to embrace hatred.
Hell, I have to say this feud is one of the best that Kane has offered. What with the promos, Cena's reactions and the audience coming into add fuel to the fire, if Kane can turn Cena and give him the Attitude Adjustment that everyone's been waiting for, it would be nothing short of amazing.