I see where Darth is coming from, but I have to take KrayZ's side.

Like he said, when you read a book, you can sort of picture what is going on. Then when it gets made into a film, specifically the ones who try to stay as close to the book as possible, it just completely wows you. The successful ones at least... such as LotR and Harry Potter like KrayZ mentioned.

Mangas are pretty much the same, except they also have pictures which gives you a more specific look at what's going on. So when the animation doesn't meet your standards, you complain about how shitty the animation is.