Once the cookie crumbles, you’re left with a mess that just goes everywhere.
I like watching animation. I think the craft is admirable, and the amount of different things you can do with it is really quite surprising. Still, not everything is equally good. Some works instantly jump out as pretty and stylistically coherent, others make you groan because they’re so bad. But the worst of the bunch is somewhere in between, near the better end of the spectrum, where it all looks good until one or two minor flaws start shining through.
For example, in modern animation, it’s fairly common to use 3D modeling for animating complex scenes, things that would take far too much time to do by hand. And in backgrounds, yeah, that’s sort of acceptable. But when I can clearly see a scene has been done fully in 3D, and that isn’t the style they had adhered to up till then, it just breaks it for me. It shows you what to look for, and afterwards even the tiniest hint of “we used 3D for this” is visible to you.
This goes even for more traditional methods of animation, like layering different images on top of each other and just moving them around on the screen. It’s a common part of the “old animation” aesthetic, but if it’s good enough it’s not noticeable at all. After you’ve seen it been used very obviously in one scene though, your mind start looking for it in everything else. No longer are characters part of their world, they slide around on top of it.
Of course all that is fine when used for comedic or stylistic effect, but if it’s inconsistent then it just trips your viewers up.