I'd have to say Pokemon started to suck after they left Johto. I mean it just became so repetitive and boring. EVERYTHING IS HAPPY, ASH GETS A BADGE, BROCK HITS ON NURSE JOY, BROCK HITS ON OFFICER JENNY, TEAM ROCKET ATTACKS, PIKACHU USES THUNDERBOLT, BLASTING OFF AGAIN, ASH IS STUPID, MEOWTH THAT'S RIGHT. Argh!! Come up with something else guys, it can't be that hard!
I still love the games though (the main series RPG games only)
However the worst anime of all time would have to be:
BAKUGAN BATTLE BRAWLERS!! (dun dun duuuuuuuuun)
The plot is so confusing, the characters are all loud and obnoxious, and there is no originality what so ever. The card game is pretty much the same as any card game (mainly Yu-Gi-Oh) and the story also has a Yu-Gi-Oh-like feel to it (saving the world from eternal darkness using mystical cards). Plus the animation is just awful. I mean, y'know how some anime like DBZ or Pokemon used to repeat some repeated scenes back in the early days? Well those show don't really do that much anymore, but his one does it all the time! We could pretty much just be watching the same episode over and over and over again. The characters are all like those from Naruto and other anime, almost like exact copies. In fact, I can provide a list of comparisons for these characters!
(I never got around to learning their names)
Red Guy = Naruto + Ash - raspy voice + loud voice
Purple Guy = Sasuke - awesomeness & dark past
Short Guy = Pikachu + glasses
Orange haired girl = Hinata
I'd like to continue but now my brain is stating to hurt...