The Armin Tanzarian and Panda Rape shows seem to get a lot of hate on this board. Though I think the Panda Rape episode was atrocious, I actually didn’t mind Armin Tanzarian so much in that it was at least an entertaining episode, and the writers pretty much acknowledged the ridiculousness of the idea by saying they would never mention it again.
Personally my candidate for worst episode would be the 13th season show “Homer the Moe.” It has all the hallmarks of post-season 10 Simpsons (when IMO it started jumping the shark):
Pointless celebrity cameo (in the form of REM)- Check.
Characters acting weird toward said celebrities (in this case Lenny watching one of the band members take a piss) - Check.
Recycling an idea that was much funnier the first time around (in this case Moe turning his bar into trendy nightspot, which was done in the Flaming Moe episode)- Check.
Characters acting out of character (Moe being a hipster) - Check.
Sober Barney - Check.
Homer acting like an obnoxious ass - most definitely.
So what Simpsons episode do you want to never see rerun again?