Deadman wonderland Worst anime ever they missed important characters in the manga the plot is boring and all the characters are not interesting even the developers think the anime is boring the manga is better
Mars of Destruction. That's not to say it's not hilarious to watch, because it is. But if there is actually such a thing as an "objectively bad" anime, hands down, this is the one. Absolute trainwreck.
For me, personally. One Piece. Why? Because it's mainstream and I hate the animations. The animations looks like someone gave birth, threw up, and took a shit.
I personally find many of the arcs and jokes hit or miss but that is the same with any long running series. The characters are overall solid and the setting lends itself well to its style. It is overrated but no where near horrible.