Fan-service. Whenever I call anime like Violet Ever-Garden,SAO, Fate/Apocrypha, and Divine Gate fan-service anime people don't wanna listen to it.
These anime all have INCREDIBLE ANIMATION. SAO and violet-evergarden got a lot of advertisement and there was quite the focus on the animation and art. Violet-evergarden is getting very hyped like some other anime I've seen and it's focus is on it's art and people think it's going to be good. I'll hold my tongue and wait. SAO had a lot of advertisement and a lot of focus on animation and art.
Divine Gate is an anime with incredible animation but the story just wasn't that interesting for me. Fate/Apocropha has incredible fights and animation but the story wasn't that interesting for me.
A anime doesn't have to have good animation, it shouldn't have to be a requirement. As long as it's not shit, it's fine. As long as the animation is decent, Im fine with it. But when it goes over the top, that's when I call it fan-service. Besides looking pretty or cool, good animation doesn't add to plot or progress it. it just looks cool and badass.
Good animation is fan-service, decent animation is well, just that, "decent" and bad animation is just bad.