When a nice, normal character suddenly goes into a rage, you've hit his Berserk Button.
Typically, when fans jump the rail or even flinch in a threatening manner toward a wrestler, the wrestler's first act is to beat the holy hell out of the fan. Even referees are not to be messed with.
Festus was a Gentle Giant until the bell rang, thus triggering his Berserk Button.
And it worked in reverse, too; when the bell rang again, usually after a victory, Festus visibly reverted to his gentle self. Genre Savvy opponents took advantage by ringing the bell themselves, forcing his tag team partner Jesse to ring it again to re-trigger him.
A sure way to bring out a certain wrestler to interrupt a promo is to say something that plays on his Catch Phrase. For example, the time Booker T said his own Catch Phrase, "Don't hate the playah, hate the game" to Triple H, who is also nicknamed 'The Game'.
A documentary on pro wrestling showed a clip from an interview with Vader. He was a nice guy, but that stopped when the interviewer asked him if wrestling was fake. Leon slapped him in the head several times and said, "Does that feel fake to you?!"
Another earlier incident had David Schultz being asked by John Stossel, who was doing an investigative report on pro wrestling. According to Schultz, Vince McMahon told him to beat up Stossel, threatening to fire Schultz if he didn't. Schultz's career pretty much disappeared after that.
André the Giant, normally a Gentle Giant, was taunted about his size by some mooks outside a bar in Europe; they then got into their car to drive away, but Andre grabbed the car and tipped it over, with all four of them inside it.
Another time, in the waning years of his career (his gigantism had made even standing too long painful), Andre became so disgusted with The Ultimate Warrior constantly hitting him too hard with a sloppy clothesline night after night, he simply put up his fist and Warrior ran right into it, knocking himself out. The next night, Warrior was gentle as a lamb with Andre. Back in the locker room, Bobby Heenan said Andre told him "He'll learn."
Don't ever call Homicide your "nizzle" unless you're in the mood to drink Drano.
Threatening Lacey with a railroad spike is a surefire way to have either Austin Aries or Jimmy Jacobs attempt to murder someone.
Tipping or spilling the APA (Faarooq and Bradshaw)'s beer is just asking for them to beat your ass.
GreenLanternFan is one of the most reviled figures in wrestling, even moreso than Vince Russo. That said, if you want to infuriate a horde of smarks, bring his name up in conversation. Steve Corino absolutely hates the man, going as far as to insult his family at ROH's "Fight of the Century." Allison Danger, Bully Ray, and Eddie Kingston also have less than zero respect for him.
Matt Striker is slowly becoming this for Lawler, as well.
Don't touch "Dashing" Cody Rhodes' face, unless you want to see him throw a huge tantrum and run towards the nearest mirror to check his reflection.
Attacking HBK's family or faith in any way— physically, mentally, financially— is a great way to communicate to him you really don't need your bones anymore. Vince McMahon, Chris Jericho, and JBL all discovered this the hard way.
In a July 11, 2011 promo, John Cena claimed that he was an underdog to CM Punk... but then Punk retaliated that he was the underdog, while Cena was the face of the company. And then rubbed salt into the wound when he compared him to his "hometown" (West Newbury, MA, but the show was in Boston so that's what got named) - going over its underdog history as insinuators of the American Revolution and the Boston Red Sox - but saying that now they were a dynasty, they'd become the New York Yankees. Cena promptly punched him in the face.
Cena's best bud, Zack Ryder is definitely off limits. Once you go after Ryder, Cena will definitely give you an attitude adjustment, and then some. Look no further than Cena beating the holy freaking hell out of Jack Swagger on the 1/16/20 edition of Raw for proof.
Oh, good God. Don't even think about making personal attacks towards either the mother, father, or sister of CM Punk. Just ask Christian on exactly whynote Though Christian didn't even attack Punk's family, he just happened to be on the receiving end of an epic ass-kicking after Chris Jericho (the actual perpetrator) verbally mocked Punk's mother and father..
Paul Heyman brought up Punk's estrangement with his biological family and said that the fans were the only family he had — a comment that all the commentators, heel-commentator JBL included, thought was too personal. Punk's expression turned downright MURDEROUS, and there was no doubt that any thoughts of mercy that Punk had for his former best friend died right then and there.
On a slightly related note: Don't taunt a former Professional Wrestler turned Mixed Martial Artist by wearing a Rey Mysterio Jr mask to your match with him as Mike Cook unfortunately did to Bobby Lashley. Bobby was visibly annoyed and then proceeded to choke Cook out. The entire match barely lasted 25 seconds.
In the spring of 2006, Kane's Berserk Button became any mention of the date May 19th. This was the day his mother and stepfamily died in a fire. It was also the date of release for his film See No Evil.
It was also the date of the infamous Clique farewell, where Shawn Michaels, Razor Ramon, Diesel and Hunter Hearst Helmsley broke Kayfabe by engaging in a group hug at Madison Square Garden on what was Diesel's and Razor's last appearance before going off to WCW. Shawn was the WWE Champion at the time, so he was untouchable and Diesel and Razor were leaving. This left Hunter to take the fall, losing his push to King of the Ring and getting saddled with months of jobbing for Jake "The Snake" Roberts and "Wildman" Marc Mero.
May 19, 1991 was also the date of the first WCW SuperBrawl PPV, featuring the debut of Kevin Nash's Oz gimmick.
A year earlier, it was the date of the NWA Capitol Combat PPV, which featured another huge WrestleCrap moment, RoboCop rescuing Sting from a ringside cage after he had been attacked by the Four Horsemen.
In the 1980s, the Mongolian Stomper did a gimmick where he had to wear protective headgear, since he would normally be unstoppable but if the fans cheered too much for his opponents he would become disoriented and unable to stop his Face opponents from making comebacks and winning.
For former "YES!" ManDaniel Bryan, people shouting "YES!" at him has been a major Berserk Button since Summer 2012, as he'll tend to respond to these shouts with a very annoyed "NO!"
During the holidays, it’s a bad idea to run over Santa Claus, regardless on whose fault it is. Alberto Del Rio found this out on the Christmas Eve episode of Raw, and as punishment, he had to fight John Cena.
Suggest to either Triple H or Stephanie McMahon that their ruthless or juvenile tendencies in the ring, on the mic, or in the boardroom will have any negative effects on their children. You may have a point, but God help you, they will make sure your ass gets beat for it.
Disrespecting a popular deceased wrestler or personality (such as Owen Hart, Eddie Guerrero, or Paul Bearer) anywhere that someone in the business who was close to them in life is in proximity to hear it and do something about it is the quickest way to be told off to hell or beaten down (the latter more likely if the incident is kayfabe).