ShiftaQuertalthough it generally works that way, mainstream doesn't necessarily mean "bad quality". Shingeki no Kyojin's excellence is overshadowed by its popularity which obviously generates controversy and unnecessary drama/equivocated criticism.
trust me, if nobody knew about attack on titan, then no one would have anything bad to say about it.
calling bs. My old housemates made me watch that with them and I didn't enjoy it at all. Perfectly reasonable that someone might criticise it.
subjective likes and dislikes do not account into criticism. real criticism is funded in the objective analysis into a work's fundamental characteristics in a given medium, which literally nobody does. someone can like something bad just as much someone can dislike something good. the likes and dislikes do not define an anime in its essence, just its general popularity and how its viewed by the media.
also, with just the little information you released, i can pretty much think about plenty of reasons why you wouldn't like it that doesn't include the anime itself being bad...not that i feel like i should expand on this.