How Bad Writers Are Good
If a novelist is really good at novelling then whenever something weird/unnecessary/contrived happens in the novel, you KNOW that thing will have plot relevance later, because otherwise it wouldn't be there.
I feel this way about Connie Willis, for example: when someone behaves unrealistically in her novels I know that's going to be a contrivance required for later, because she's too good to have unnecessary things happen unnecessarily.
(I guess the best novelists would make it so that the plot-relevant items aren't contrived either, and where you're in such a flow state while reading them that you don't notice when the big clues get slipped right in front of you, but who among us has such talents?)
This has weird consequences: in some ways, worse novelists are in some ways better to read, because when weird stuff happens it might just be because they don't control their writing super well.
For example, I actually really like Brandon Sanderson, and over time I've come to realise that he's super tightly controlled in his own way, but the first time I read one of his books and the protagonist went on a long unnecessary spiel about guns I remember thinking "this might be a case of literal Chekhov's gun, but also this guy might just be a ridiculous writer who really likes talking about guns, so he's self-inserting his hobby here like those ridiculous land-reform sections in Anna Karenina." As a result, I really couldn't tell whether the information was ever going to be relevant, and this increased my overall surprise in the novel.
By the way, for many years I had this (specious) Did You Know in my head about Chekhov's Gun, namely, that Chekhov originally meant it as a complaint rather than an imperative: the problem with theater, he was saying, is that if you see a gun on the wall in the first act you know (from previous theater experience) that it will go off in the third, so the surprise is ruined, versus in real life where there are tons of random superfluous details everywhere and you never know what is going to matter or not.
I have tried to fact-check this a bunch of times and not only can I not-find support for this claim, I have pretty repeatedly found people saying that what Chekhov meant by his Gun is pretty much what everyone thinks he meant by his gun. [EDIT: commenter Alex kindly confirms!] So I'm going to tentatively claim this thought for myself instead and call it Uri's Gun: the problem with fiction is that if at literally any point the author lingers over a gun, you know it's going to go off eventually, and that ruins some of the surprise.