4Kids' One Piece, The Belle Of The Brawl: Oh God, I can't believe that 4Kids actually went through with this atrocity. The merging of several episodes, the edits that made massive continuity error, the lack of any emotion, and of course the dungeon edit. It's the lowest point of the dub version of the Arlong arc, which is IMHO the lowest point of the dub in general.
Mega Man, "Curse Of The Lion Men": The plot is just says it's awful, "Lion men come back to life thanks to a comet and turn people into lion people". The crappy animation helps this as being the worst of the show as well.
Transformers G1, "Megatron's Master Plan" Parts 1 & 2: Apparently, his master plan is using bad press to make the Autobot's look bad. How can the mayor of a city exile the Autobots off Earth? Shouldn't that be the decision of the UN or something. Then there's the fact that Spike was apparently chased by Ravage for who knows how long between Part 1 & 2. They couldn't spare us Parts 2 by just having Spike showing the truth and the Decepticons flying off in defeat yet again.
Captain N, "Happy Birthday, Megaman": As a Mega Man fanboy whose actually likes the show, I can't stand this episode. The plot is inane, Mega Man's urge to be human is completely random. It just felt boring for the most part. There was no true villain, just minor obstacles. The ending is what pisses me off the most, Mega Man actually became a human. Though that would be retconned by the second and third season writers.
Bleach, Epiosde 50: "The Reving Lion": I don't want to retread this rant, click this link to see my said rant.
http://forums.rabroad.net/showpost.php?p=2658814&postcount=65