Some deserve some honorable mentions.
Rey vs Eddie: Custody of Dominick
Rey Mysterio's son Dominick was involved in a storyline where Eddie Guerrero comes out to say he is the real father and Rey has just been caring for him. Then Dominick was ringside for every one of their matches, and although Dominick knew he was part of a storyline, it is too much to put a little kid through that. It is really uncomfortable to watch real life members of the wrestler's family involved (as in non-wrestlers) and when a kid is in the mix and being told that someone else could be the father and he will battle his other father for custody was plain wrong and a real downfall moment in both their legendary careers.
HBK and God vs Vince & Shane McMahon
It has been widely known for years that Shawn Michaels is a born again Christian. In 2006 a storyline began where Vince McMahon would mock HBK's beliefs. The envelope was pushed on this storyline to the point where WWE.com wrote an article hyping an HBK/Shane McMahon match which deliberately referred to Vince McMahon as God and Shane McMahon as Jesus Christ. If that wasn't enough, a match was advertised for Backlash pitting the McMahons against HBK and God!! Exploiting HBK's faith was one bad thing, but for Vince to try to refer himself as God was distasteful.
Other Honorable Mentions.
The Edge/Lita/Matt Hardy love triangle was very harsh for all those involved, but especially Matt Hardy. Matt Hardy was with Lita, but she ended up dating Edge in real life. And to make matters worse, WWE put all three in a storyline so they can relive that. What were they thinking? Seriously?
And another that involved a real life issue? The CM Punk vs Jeff Hardy storyline. CM Punk constantly brought up real life issues about Jeff Hardy, who in an interview after his release showed his disgust at the storyline and how WWE treated his personal issues. Within that storyline, they showed him being attacked in a pyro incident, being attacked in a stairwell and brought up on TMZ and WWE.com as if it was real, and a car crash in order to make his life seem even worse. And when his house was up in flames, WWE thought they could exploit that also. Wow, WWE really did not know when to stop until Jeff actually decided enough was enough and went to TNA. Can you blame him?
We then have little ones such as Val Venis and Kai En Tai storyline where Val Venis showed Kai En Tai's manager Yamaguchi-San a pornographic video of Venis sleeping with Yamaguchi-San's wife. And to make matters worse, they punished Val Venis by stripping him naked and whipping him, and showed what looked like them using a samurai sword to chop off his penis.
So there are the top 10 most despicable storylines ever in the WWE, and still to this day makes you think what twisted minds they must have had to think of things like that!