Speculation is still running rampant as to whether CM Punk's walk out was a work or if he truly is gone from the company, but for right now, we have to operate under the assumption that he is gone.
If he really is done with WWE, then that means the possibility exists that we will never see the Best in the World inside a WWE ring ever again. It's a small possibility, but one that still exists.
That means that the run he had from 2006 through the beginning of 2014 is what we have to look back on to remember the man that turned WWE upside down.
Punk has had many memorable feuds throughout his nearly eight-year run with the company, but there are a few that stand out as the most memorable.
Hopefully, the Second City Savior is not done with WWE, but let's look back on his five greatest feuds from his WWE career.
CM Punk and Rey Mysterio have had many matches in WWE, but their feud during Punk's time as the leader of the Straight Edge Society will always be looked at as their best work.
Punk and Mysterio feuded for months, with several pay-per-view matches and plenty of drama. The most memorable segment involved CM Punk interrupting a celebration for Rey's daughter where he would sing "Happy Birthday" to her in a very creepy way.
Their feud began when Rey Mysterio eliminated Punk during the Elimination Chamber pay-per-view in 2010. They continued their feud with singles matches at WrestleMania 26, Extreme Rules and Over the Limit, as well as at the Fatal-4-Way PPV.
Rey was the seasoned veteran at this point, but Punk was still working to establish his place in the company, and this feud certainly showed his capacity to carry a program and be a top star.
The Best in the World vs. The Best in the World at What He Does was a match made in heaven. CM Punk and Chris Jericho are two of the most talented performers WWE has ever seen, and a big-money feud between them was a long time coming.
Punk and Jericho had clashed in the past, but that was when Punk was a midcarder clawing his way up the ladder. This time around, they were both top names in the company.
Their feud spanned three PPVs, beginning at the Elimination Chamber in 2012. They continued with singles matches at WrestleMania and Extreme Rules.
Punk was successful in all three matches, effectively giving him the claim to the nickname "Best in the World."
I was lucky enough to be in attendance for the Chicago Street Fight at Extreme Rules 2012, and it was a great way to end this feud.
This feud was mostly driven by matches featuring other Superstars, but it was the story of Paul Heyman and CM Punk that drove the whole thing home.
This feud saw Punk face Brock Lesnar at SummerSlam and several matches with Ryback and Curtis Axel across several months.
It all started when Paul Heyman turned on Punk during the Money in the Bank PPV, costing him his shot at becoming a three-time winner of the coveted briefcase.
The end of the feud saw CM Punk defeat Ryback and Heyman inside Hell in a Cell, but Punk truly got his revenge on his former manager after the match was over.
Punk delivered dozens of kendo stick shots to Heyman on top of the cell, delighting fans and putting Heyman out of action.
The mic work in this feud was one of the main highlights due to the fact that Heyman was usually not involved in the matches physically, and these two proved that it is still possible to carry a long feud with solid promos and interesting storylines.
John Cena and CM Punk have had several different feuds over the years, but the feud that saw Punk leave WWE with the title in a storyline was the one that made Punk into a true top name in WWE.
Cena and Punk had an incredible match at Money in the Bank for the title, and Punk's victory allowed him to leave at the end of his contract as the reigning champion in his hometown of Chicago, IL.
John Cena won a new WWE Championship, and Punk returned during his celebration to declare himself as the rightful holder of the title.
With two men having valid claims to the championship, Triple H had no choice but to make a title vs. title match at SummerSlam to crown one true WWE champion.
Punk would walk away with the title, but his victory was short-lived as Alberto Del Rio decided to cash in his MITB briefcase moments after Punk's victory.
John Cena may get flack from a lot of fans, but nobody can deny that Punk and Cena have always brought out the best in each other during their matches and promos. This feud proves it.
CM Punk's straight-edge lifestyle and Jeff Hardy's well-known issues with substance abuse made the two a perfect fit for a feud, and adding the world title to the mix only upped the stakes for both men.
The real-life aspects of this feud are what made it so interesting, and it was made even more interesting by the fact that the clean-living Punk was the bad guy in this scenario.
Punk claiming that his lifestyle made him better than Hardy allowed Hardy to gain more support from fans who felt that he had earned his redemption.
The two had a great feud that would see Punk turn heel in the process. It all started when CM Punk cashed in his MITB briefcase on Jeff Hardy just moments after Hardy had won the world title from Edge in a ladder match at Extreme Rules 2009.
Punk retained his title against Hardy in a triple-threat match on Raw and in a match at The Bash, which saw Punk get disqualified to keep the belt.
Hardy would regain the title at Night of Champions, but the Charismatic Enigma would have yet another short reign as Punk won the title back from Hardy at SummerSlam in a TLC match.
The feud culminated in a Steel Cage match on SmackDown, where Hardy would have to leave WWE if he lost. Punk won the match and sent Hardy packing from WWE.
CM Punk has had a lot of great feuds in WWE, but these five were the best. Then again, this is just my opinion. What's your opinion? How would you rank the feuds, and was anything left off the list that you think deserved inclusion?
Thanks for reading, and follow me on Twitter @BR_Doctor.