objectively bad? Green Green. If you don't believe me, just try to watch it. It was bad at the time, and it aged worse than Love Hina.

something I absolutely despised? Rosario † Vampire adaptation. For the first chunk, the manga was a dopey romcom with fanservice, and it was fairly generic and rather underwhelming. Then it did a 90 degree genre shift and became more of a battle shonen thing that was done quite well. The anime crew wanted to continue the with the dopey romcom shit and do so while bringing in the newer characters introduced in the manga after the genre shift. The only problem was that the anime crew had no idea how to write or direct something new and without the manga providing them a storyboard for the plot, and all of the new characters had their personalities altered in an attempt to better fit in with the dopey, stereotypical highschool fanservice part. It was a bad, and the writers and director should be shot.

>>29192
the worst part is that I'm actually a fan of the 3 green green games but it at least had some stuff that was funny, stuff like girls bravo and boys be fits in there as well as crappy fanservice comedies that are just way too crude and often fail at just about every attempt at humor.
And on the note of stuff that didn't age well, sister princess really did not hold up even though I still enjoyed some of the dumb jokes.

The worst thing I've ever seen though was probably nekogami yaoyorozu (it only aired some years back, but it's just awful, in the art, sound, writing, voice acting) or infinite ryvius (the writing is just terrible).
Most the bad anime I've seen that's more than 20 years old was clearly made for kids so I'm able to forgive their issues on some level, but I'm sure of all the 90s and 80s OVAs out there, there are some really awful ones on par with musashi gundoh, md geist, and mars of destruction.

>>29206
>nekogami yaoyorozu
I really wanted to like that anime when it aired, but they sure didn't make it easy. Personally I liked the art and thought it was cute, I think it even had a decent first ep. That's about all the nice things I can say for that Touhou wannabe. Because then the author self inserted hard and dragged the whole series down with them. It was mind blowing how far the creator had their head up their own ass. Their insert character couldn't have been more out of place, yet a large amount of the second half was dedicated to themselves with other characters helping her create manga as if that'd be cute or funny. Maybe if it was a 4th wall breaking gag comedy that crap might fly, but for Nekogami is was just weird and distracting. It'd be like getting halfway into a touhou game before being stopped by a 2D version of Zun who puts the story on hold and makes you to help him program the rest of the game. Like what the fuck? Go make a webcomic for that shit, don't ruin your story with it.