Hulk Hogan: Has had a number of these, most of them involving friends turning on him. One of the most notable was during the summer of 1990 as the set-up to his feud with Earthquake. To take some time off to heal from legit injuries and tend to movie-making projects, Hogan (who had earlier dropped his WWF World Championship to the Ultimate Warrior) and John Tenta, who was being pushed as an unstoppable monster heel with his Earthquake character, agreed to a storyline where Earthquake would sneak attack Hogan on the set of "The Brother Love Show" and repeatedly use his sit-down splash to break Hogan's ribs. During Hogan's absence, WWF announcers explained that Hogan had entered into a BSOD-like state; his "injuries" from the attack coupled with his WWF title loss took such a toll on his fighting spirit that he wanted to retire. Viewers were asked to write letters to Hogan and send postcards asking for his return (they got a postcard-sized picture in return, autographed by Hogan, as a "thank-you"), and the result was predictable: Hogan and his fighting spirit were "rejuvinated" and, with a well-timed breaking out of his catatonic state, swore revenge on Earthquake and got it.
In the 2010 Royal Rumble, one of the biggest stories going in was Shawn Michaels' desire to face The Undertaker at Wrestlemania in order to try and avenge his loss to him the year prior (in a match that was widely considered to be the best of 2009), an since Taker is the current World Heavyweight Champion, the only way for Michaels to have a guaranteed stab at him was to win the Rumble match itself and challenge him at Mania. So in the Rumble match itself, Shawn Michaels survives a long stretch of the match (eliminating Triple H, his own tag team partner, in the process) and makes the final four, where he... goes out first, at the hands of Batista. The BSOD ensues immediately afterwards, only broken up briefly by Michaels trying to go back into the ring and taking his frustrations out on the referees before returning to a near-catatonic state.
Michaels seems to be particularly prone to these. He had already experienced one at the 2008 Unforgiven pay-per-view, where he challenged Chris Jericho to an Unsanctioned Match after Jericho punched his wife in the face. He whipped his enemy with a belt, injuring him so grievously that Jericho went into shock. The bell was rung, and an announcer declared Michaels the winner of the fight. By this point, however, Michaels was so consumed with rage that his face had gone completely blank and he was continuing to mindlessly whale away on the unconscious Jericho as if he didn't understand what he was doing. He finally snapped out of his stupor after a referee tried to stop him and he kicked the official in the face; he then had a My God, What Have I Done? moment and finally agreed to leave the ring.
HBK's biggest BSOD came after the 1996 Survivor Series. Not only did the NYC crowd boo him during his WWF Championship defense against Sycho Sid, but Sid resorted to taking out Jose Lothario out with a camera to completely demoralize Shawn. Sid ended up winning the WWF Championship.
During the third encounter at WrestleMania between The Undertaker and Triple H in their Hell in a Cell match, were Shawn was the guest referee, at one point during the match things had gotten to the point of Shawn being told by the Undertaker not to stop the match no matter what happened. This was after 'Taker taken a few chair shots to the back and Triple H had just gotten the same in return. Shawn was sitting in the corner of the ring looking like was having a nervous breakdown while Undertaker and Triple H was trying to get to their feet after a two count had occurred.
At Wrestlemania VII, Ultimate Warrior wrestled "Macho Man" Randy Savage in a Retirement Match. During the course of the match, Warrior hits Savage with his Five Moves of Doom, and to his horror only gets a two-count. He looks at his hands, has a BSOD, and then decides to leave the match. He is brought back into the match after Sherri Martel foolishly attacked him, and wins after three shoulderblocks.
CM Punk suffered one when, after beating The Miz in a recent match, Jericho comes on the Titantron and talks about how he's pinpointed a weakness of Punk's: His alcoholic father, whose bad habits were the reason Punk became devoted to the Straightedge lifestyle. Jericho picked apart Punk's character and Straightedge morals and promised that after he beat Punk for the WWE title, he'd help Punk "drink" his loss away. After all of this, Punk, for the first time as far as we've known him, didn't say a word. He picked up his championship title, and walked away with a far-away look in his eyes.
In a tragic Real Life example, Jerry Lawler's reaction to Owen Hart's soon to be fatal fall at WWF Over The Edge 1999.