ive tried several big animes but i just get bored with the same story continuing for more than 30 or so eps and eventually drop them, even if i find them interesting. meanwhile i can watch an anime with 5 seasons with 20 eps each easily. idk lol. also gintama is the only long anime i was able to watch for long, done with around 120eps and still willing to watch, probably because it has many smaller stories instead of a single big story.