Bad endings/unfinished stories and poor adaptations.
Pretty much this. One of my fav. series, Toriko got this treatment. Not only did it have a bad ending but it also had a poor adaptation overall with extreme censorship and altering major plot points. In fact, with the recent Toriko chapters it shows how poor of an adaptation the Toriko anime is.
When the anime is terribly paced and/or doesn't follow the source material. Don't forget shitty animation.
This can be annoying as well, One Piece suffers from terribly pacing with one chapter per episode pacing. Sometimes it covers half a chapter per episode. Inconsistent animation is annoying af.
Well u basically hate every Shonen anime then XD
Toriko has no tsundere characters, so that's false.
Btw, you can tell if a series will have a new season or not. If it ended on a filler ending, it's pretty much guaranteed it won't have a next season and if the sales aren't doing well in general. That's pretty much what you look at.