> They still expect a consistent user interface but seeing a menu not render exactly where it should, an animation that stutters for one frame or other small things. These are all things that we as developers scrutinize but the user doesn't notice all that often.

I find it's the other way around. Quite often it's the developers who don't care if a menu is out of place or if an animation stutters.

The users, however, do see these things. They might not be able to articulate it, but they will see it. And call your app slow (animation stutters), unpolished (menu not rendered where it should) etc.

That's why, for example, MacOS has been getting so much flak these past years: they've stopped sweating the little details, and people noticed.