WWE can call the last 15 years the Ruthless Aggression era and the PG era, but in reality, the last decade and a half in the WWE has been the era of John Cena. In that time frame, Cena has won 16 World Championships and has wrestled just about every top guy in professional wrestling. In his time with the WWE John Cena has made a lot of friends, but he has also made a lot of enemies, so we're listing 15 of the former, and 15 of the latter.

I have tried to make this list comprehensive but to make it interesting most of the superstars talked about here have had noteworthy professional wrestling careers. Whenever possible, I have included direct quotes from Cena himself, or quotes from other wrestlers about the Doctor of Thuganomics. This list makes it clear how easily strong feelings can emerge between wrestlers who spend most of their careers out on the road together. If you can think of any wrestlers that Cena is friends with (or that he hates) that didn't make our list, feel free to mention them in the comments.

30 Friends - Cesaro

John Cena is often called the Superman of the WWE, so it is unsurprising that he has developed a lasting friendship with "The Swiss Superman" Cesaro. The two have never matched up in a long-term rivalry (or tag team) together, but I'd be lying if I said I wasn't interested in watching them throw down. You can say what you want about Cena, but his mic skills are second to none. By comparison, Cesaro can lack real aptitude on the mic, but has unparalleled in-ring ability. If these two ever match up for any significant length of time, I have no doubt that the results would be magic. The friendship that they have developed would only add to their in-ring chemistry, and the fact that these two are able to trust each other in the gym shows how they would be able to trust each other in the squared circle.

29 Dislikes - Alex Riley

This next entry kind of surprises me, for no other reason than I didn't think Alex Riley was in the WWE long enough to make his share of enemies. In his short time with the company he was involved in the heated rivalry between John Cena and The Miz. As The Miz's manager, Riley had quite a few matches with Cena. Apparently, Cena wasn't a fan of Riley's in-ring style. The veteran not only criticized Riley's wrestling to his face, he told everyone backstage who would listen how terrible he was. According to rumors, Cena even went so far as to check Riley's bag for illegal substances. Cena never found the evidence to get Riley fired, but the influence of the 16-time champion likely led to the young Superstar falling out of favor with the WWE.

28 Friends - Daniel Bryan

This entry is obviously low hanging fruit, but sometimes those fruits are also the ripest. Not only are John Cena and Daniel Bryan close friends, they are practically brothers. A few years ago, Bryan married Brie Bella (of the Bella Twins), and the pair recently had their first child together. John Cena, meanwhile, proposed to Nikki Bella at last year's WrestleMania, although the couple recently split up. Not all relatives get along, but it seems like Cena and Bryan have a legitimate respect for one another. The two had a memorable championship match at SummerSlam, and they are the two Superstars who seem to have the purest love for professional wrestling. It is still crazy to me that two of the companies' top faces would end up becoming brothers-in-law.

27 Dislikes - Chavo Guerrero

Considering the fact that Chavo Guerrero was never even close to being considered a top star in WWE, it is hard to imagine where he got the animosity that was evident in his 2013 interview with Fox News. During his interview he had some harsh criticism for Cena's in-ring wrestling skills. He said " If he can't wrestle, then he can't wrestle, you know? Very, very few and far between do we get a Triple H or a Rey Mysterio, a Randy Orton. That doesn't happen too much anymore... You can tell who's making John Cena look good." If this wasn't bad enough, Guerrero went on to say that he would stop watching WWE if Cena wins his 17th World Championship and surpasses Ric Flair on the all-time list.

26 Friends - Samoa Joe

As a longtime company man, most of the wrestlers that John Cena is friends with have spent a lot of time in WWE. Our next entry is unique then, because Cena actually met Samoa Joe before either wrestler was a WWE Superstar. Can we start off our entry with our astonishment that WWE had Samoa Joe within their clutches at Ohio Valley Wrestling (OVW), but didn't sign him to a main roster contract? But then again, this was the most stacked OVW class of all time; the roster included Cena, Brock Lesnar, Randy Orton, and Batista. It was during their time at OVW that Cena and Joe developed a close friendship. They mostly lost touch over the years, but since Joe's return to WWE the two have been spotted together.

25 Dislikes - Roman Reigns

One thing that has been great about the past few years is that John Cena has finally put to rest the persistent rumor that he keeps down younger WWE talent. In the past year alone, he has lost big matches to AJ Styles, Shinsuke Nakamura, and Roman Reigns. If I had to guess, I would say that last name is the one that keeps John Cena up at night. People have compared Reigns' career trajectory to the push Cena was given in 2005, however, the two wrestlers couldn't be more different. Many wresters have complained about Reigns' arrogance, and a failed drug test has even given some top officials pause when proclaiming him as the WWE's top guy. Cena is all about respect for the WWE, and I can't imagine that some of Reigns' antics have sat well with him.

24 Friends - Chris Jericho

Despite being rivals for a good part of their careers, John Cena and Chris Jericho have formed a lasting friendship with one another. When talking about their friendship, everyone brings up the story that Jericho told on his own podcast. After a night of drinking Cena took a heavily intoxicated Jericho back to his house. Y2J immediately went to sleep, but Cena (who was apparently almost as drunk as Jericho himself) stayed up the whole night listening to Jericho's music collection. Now one story doesn't make a friendship, but both Cena and Jericho have been part of the WWE since the early 2000's. Not only that, both have been influential members of the locker room, and both have a great love for the professional wrestling business.

23 Dislikes - Brad Maddox

A lot of speculation went into this next entry, but I think there are enough facts to make the argument that John Cena probably isn't the biggest fan of Brad Maddox. Maddox got his start in WWE as a crooked referee and ended up getting enough attention that he was named the General Manager of Monday Night Raw. Eventually he began a career as a wrestler before he was abruptly released by the WWE. It turns out that a big reason for Maddox being let go was a series of elicit videos featuring him and WWE Diva, Paige. The worst of these involved an unsavory act with the NXT Women's Title. I can't imagine that this kind of disrespect for a WWE championship went over well with "the face that runs the place."

22 Friends - Big E

It seems like John Cena is willing to become friends with anyone who will power lift with him. With that being said, the friendship between Cena and Big E actually makes a lot of sense. Both are quintessential gym rats, both have a unique, goofy sense of humor, and both have been with the WWE for their entire professional wrestling careers. One of Big E's first rivalries in the WWE, in fact, was against the leader of the CeNation. Big E (then known as Big E Langston) was the valet for Dolph Ziggler at the time, and the Show-off was involved in a heated dispute with Cena over which one of them was actually the better wrestler. The two have been friends ever since, and there is significant photo and video evidence to show them hanging out together. Most of these photos are from them at the gym, but to each his own right?

21 Dislikes - Kenny Dykstra

Most of the wrestlers on this list have developed combative relationships with Cena because of professional reasons. The story of our next entry, however, is incredibly personal. Most of our readers already know the story of how John Cena had an affair with Mickie James that ended his marriage (and if you don't it is featured elsewhere on this list), but that wasn't the only friction that his affair created. Before Mickie had her tryst with Cena, she was dating Kenny Dykstra, the former member of the Spirit Squad. Dykstra reportedly voiced his opinion about Cena and James' relationship, which caused Cena to get him drafted to the SmackDown brand. Dykstra fizzled out on Friday nights, and was shortly fired from the WWE.

20 Friends - Edge

If John Cena was being inducted into the WWE Hall of Fame today, I would be willing to bet that Edge would be the man to induct him into the Hall. Edge won his first World Championship after beating John Cena at Elimination Chamber, setting off a four-year rivalry between the two. When Edge became the top face on Smackdown, it gave WWE producers the opportunity to showcase the friendship that had blossomed between him and Cena. Their friendship was featured prominently in John Cena's rivalry with Brock Lesnar and as part of the Authority storyline with Triple H and Seth Rollins. This friendship isn't solely for the cameras, however, both Cena and Edge have said in interviews that they are close friends outside of the squared circle.

19 Dislikes - Tyler Reks

So far, most of the wrestlers that John Cena has had a problem with probably deserved the ire of the 16-time World Champion. If the rumors are true about our next entry, however, then Tyler Reks has a legitimate gripe about how he was treated by Cena. At one point, Reks was a rising star in the WWE. He was over with the fans, and WWE had committed to giving him a big push on SmackDown. The problem? Reks' finishing maneuver, the Burning Hammer, is very similar to Cena's Attitude Adjustment. A story has surfaced that Cena approached Reks and told him to get a new finisher. When he didn't, Cena threatened to get Reks fired. Reks was released by the company a few months later and some fans have blamed Cena for his departure.

18 Friends - AJ Styles

SmackDown Live may be "the house that AJ Styles built," but I think the argument can be made that AJ Styles would not be such a phenomenon (pun intended) in WWE if it weren't for John Cena. Cena may have defeated Styles more times than some hardcore WWE fans would have liked, but he never "buried" him, and their high-profile matches helped Styles gain enough legitimacy to challenge for the WWE World Heavyweight Championship. When Styles arrived at WWE, his and John's careers could not have been more polar opposites. But after working together for several pay-per-views, there is now obvious respect between them. There is a short jump from respect to friendship, and the veteran wrestlers have already begun to bridge that gap.

17 Dislikes - Mr. Kennedy

Sometimes there are wrestlers who are so difficult to work with that it overcomes their immense talent. Mr. Kennedy (now Mr. Anderson) is one of these wrestlers. Kennedy was a rising star in WWE, but personal issues with other wrestlers (and a failed drug test) led to him being released by the company. One particular incident is of interest to our list. After Kennedy wrestled in a 10-man tag team match, Randy Orton complained to WWE management that his opponent was unnecessarily stiff. Cena backed up Orton on his claims. When two of WWE's top stars are complaining about you, your days are numbered with World Wrestling Entertainment. Since Kennedy's departure from WWE he has said that he blames Cena and Orton for pushing him out of WWE.

16 Friends - The Big Show

If two wrestlers have been in the WWE for over a decade together, chances are that they are pretty good friends, or that they hate one another. John Cena may have been the face of WWE for the past 12 years, but Big Show has been one of the companiy's most consistent performers since the late 90s. The two have competed in several big matches with one another, and the future WWE Hall of Famers have a lot of respect for each other. Cena's first title reign in WWE actually came at the expense of the Big Show. At WrestleMania XX, Cena managed to lift the 500-pound man, and pinned him to win the United States Title.

15 Dislikes - Ryback

Given the fact that Ryback got his big break in WWE because of an injury to John Cena, I'm surprised that he went so far to call Cena out once he left the WWE. After he was released from the WWE, "the Big Guy" had some harsh criticisms for the WWE as a whole, and its top star was no exception. During an interview Ryback said of Cena, "he has been the face for ten years, and he's really good at what he does. But everyone knows that I don't like John Cena, and he doesn't like me either." Ryback has yet to explain what caused this friction between him and Cena, but I have some guesses. Other wrestlers have called out Ryback for being too stiff, and I wouldn't be surprised if Cena had some harsh critiques about Ryback's wrestling.

14 Friends - Sheamus

There was a time when the internet wrestling community was convinced that John Cena was responsible for "burying" several up and coming superstars. The new, part-time Cena often loses to younger talent, but back when he was "the guy" for WWE, he almost never lost in important matches. This rumor was so prevalent, in fact, that IWC fans had to explain away one of the few times that Cena did appear to win clean. Sheamus won his first title with WWE when he beat John Cena at TLC 2009 for the WWE Championship. Many fans believe that Cena was supposed to win this match, but an in-ring slip up caused him to accidentally fall through the table. Maybe keeping this secret is what built the friendship between Sheamus and Cena, as the Celtic Warrior is often seen out and about with the Face that Runs the Place.

13 Dislikes - Brock Lesnar

John Cena is obviously an ambitious performer. He wants to get paid just like everyone else, and one could argue that he wants to get paid more than most other Superstars. I would never say, however, that being a professional wrestler is all about the money for Cena. Cena was a fan of the WWE growing up, and he seems to truly enjoy performing in front of the WWE Universe. The same cannot be said for the Beast Incarnate, Brock Lesnar. Lesnar has admitted that he's all about the money, and he has it written into his contract that he does not have to interact with fans. These different styles have famously led to some friction between Cena and Brock.

12 Friends - Michael Cole

If you grew up like I did watching John Cena's podcast on WWE.com, you probably thought Cena had a legitimate beef with WWE commentator Michael Cole. As I've gotten older, however, I have realized that the Doctor of Thuganomics' constant barbs at the unpopular announcer (this was at a time when the IWC legitimately disliked Cole, especially in comparison to Jim Ross) were merely a strategy to get over with the fans. In reality, Cena and Cole are close friends. Cole has talked in interviews about how much he legitimately admires Cena's in-ring work, and he has been one of the announcers who has most fervently talked up Cena in the company. I think a fair comparison can be made between the relationship of Cena and Cole, and the one between Jim Ross and Stone Cold Steve Austin.

11 Dislikes - The Rock

I wasn't sure where The Rock fit best in this article, but I knew our list would not be complete without a discussion of the tumultuous relationship between the Brahma Bull and the 16-time World Champion. Both Cena and The Rock got very heated during the buildup to their "once in a lifetime" WrestleMania match. It was obvious from the start that the two men didn't think fondly of each other. As the years have passed, however, they have gotten over many of their issues and even appeared to become friends. But recent interviews between the two have shown that there is still some animosity between these Titans of wrestling. Could all this be part of a leadup to a tiebreaking future WrestleMania match?