I've noticed quite a few games with otherwise good pixel art that are kinda...messy. That is, they'll have lines that are left jaggy (stairs), or single pixels left over from quick shading strokes, or they'll have 4 stages of a color used for smoothing, and yet leave patches with no smoothing because they just missed it.

I've worked with pixel artists before who are otherwise very talented, and yet it's like they just don't look at individual parts of a sprite to check for errors. So it's hard to tell if artists are just being lazy, being rushed, or if they really just don't even realize they're doing it.

I'd compare it to seeing a great story that has a lot of spelling mistakes. I get it, but at the same time it just kills me to see it in finished games, because it feels so unprofessional, and then people praise it like it's perfect anyway and so there's no expectation for artists to do clean work.

Well, to give a very uncontroversial example.
https://i.gyazo.com/55393eb062c7add20cf4be534cf5b43b.jpg

And here's an example from something someone linked me to recently.
https://i.gyazo.com/be6dc600113e2ea2b5dfee47a8ef6a66.png

Even with what people try to call "high bit" these days, I just look at the sky in any given shot, and it almost always seems like there's lazy shading somewhere. At this point I find it hard to enjoy pixel art games Just for the fact that all the imperfections give the impression that "someone made this", and wasn't paying attention. A lot of snes games have some janky shading, but it seems like they were almost always clean.

Edited and corrected it. Other is shot from shovel knight.