This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Eddie Guerrero
The tribute shows in November of 2005, both taped less than a day after Eddie was found dead. If the opening salute on Raw didn't get you, the tribute video will.
The horrible, horrible "Eddiesploitation" angle WWE ran after his death, widely regarded as THE worst thing the company has ever done. According to Konnan, Vince McMahon was the only person who wanted it to happen, but since he was the boss he was able to force everyone, from Eddie's best friends to his widow to take part in the crass, tasteless and degrading angles. Supposedly it was supposed to last even longer (with Chris Benoit being set to feud with Chavo over "Eddie's Estate") until Benoit, Eddie's dearest friend, finally put his foot down and told Vince he flat-out wasn't doing it. When WrestleCrap awarded the angle the Gooker Awardfor 2006, RD Reynolds didn't include any soundbites or images from the angle in the article, because the angle wasn't something he could enjoy himself mocking- it was simply loathsome, and he just couldn't bring himself to go back and go through it again to find the material.
Reynolds: On the marquee of this site, it says, “The Very Worst of Professional Wrestling.” Truly, this induction is the very embodiment of that tagline. The seemingly never ending exploitation of the late, great Eddie Guerrero is the absolute worst of pro wrestling, bar none.
Chris Benoit's death. Not only does the death erase the iconic ending of WrestleMania XX from history, but Eddie's own death played a part in it. Chris never got over it.
In particular, this part of Chris' speech during Eddie's tribute show: "He was the one friend that I had that I could go to and pour my heart out to if I was going through something, a personal issue, a personal problem. He was the one guy that I could call and talk to, and know that he'd understand and... he would talk me out of it." If Eddie had lived, it's really likely Chris Benoit, his wife and his child would still be alive today, he would still be a WWE legend, and the course of the company's history from 2008 on might be very different.